Answer in brief
CVE-2024-40910 records a Unknown severity vulnerability in ax25: Fix refcount imbalance on inbound connections. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <f4df9d6c8d4e4c818252b0419c2165d66eabd4eb || >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <52100fd74ad07b53a4666feafff1cd11436362d3 || >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964 || >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <3c34fb0bd4a4237592c5ecb5b2e2531900c55774 || c44a453ffe16eb08acdc6129ac4fa0192dbc0456 || de55a1338e6a48ff1e41ea8db1432496fbe2a62b || 9e1e088a57c23251f1cfe9601bbd90ade2ea73b9 || b20a5ab0f5fb175750c6bafd4cf12daccf00c738 || 452ae92b99062d2f6a34324eaf705a3b7eac9f8b || 534156dd4ed768e30a43de0036f45dca7c54818f || >=4.14.277 <4.15 || >=4.19.240 <4.20 || >=5.4.190 <5.5 || >=5.10.112 <5.11 || >=5.15.35 <5.16 || >=5.17.2 <5.18 | f4df9d6c8d4e4c818252b0419c2165d66eabd4eb, 52100fd74ad07b53a4666feafff1cd11436362d3, a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964, 3c34fb0bd4a4237592c5ecb5b2e2531900c55774, 4.15, 4.20, 5.5, 5.11, 5.16, 5.18 |
| Linux/Linuxgeneric | 5.18 | Not reported |
Published upstream
Jul 12, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: ax25: Fix refcount imbalance on inbound connections When releasing a socket in ax25_release(), we call netdev_put() to decrease the refcount on the associated ax.25 device. However, the execution path for accepting an incoming connection never calls netdev_hold(). This imbalance leads to refcount errors, and ultimately to kernel crashes. A typical call trace for the above situation will start with one of the following errors: refcount_t: decrement hit 0; leaking memory. refcount_t: underflow; use-after-free. And will then have a trace like: Call Trace: <TASK> ? show_regs+0x64/0x70 ? __warn+0x83/0x120 ? refcount_warn_saturate+0xb2/0x100 ? report_bug+0x158/0x190 ? prb_read_valid+0x20/0x30 ? handle_bug+0x3e/0x70 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? refcount_warn_saturate+0xb2/0x100 ? refcount_warn_saturate+0xb2/0x100 ax25_release+0x2ad/0x360 __sock_release+0x35/0xa0 sock_close+0x19/0x20 [...] On reboot (or any attempt to remove the interface), the kernel gets stuck in an infinite loop: unregister_netdevice: waiting for ax0 to become free. Usage count = 0 This patch corrects these issues by ensuring that we call netdev_hold() and ax25_dev_hold() for new connections in ax25_accept(). This makes the logic leading to ax25_accept() match the logic for ax25_bind(): in both cases we increment the refcount, which is ultimately decremented in ax25_release().
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2024-40910 records a Unknown severity vulnerability in ax25: Fix refcount imbalance on inbound connections. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <f4df9d6c8d4e4c818252b0419c2165d66eabd4eb || >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <52100fd74ad07b53a4666feafff1cd11436362d3 || >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964 || >=9fd75b66b8f68498454d685dc4ba13192ae069b0 <3c34fb0bd4a4237592c5ecb5b2e2531900c55774 || c44a453ffe16eb08acdc6129ac4fa0192dbc0456 || de55a1338e6a48ff1e41ea8db1432496fbe2a62b || 9e1e088a57c23251f1cfe9601bbd90ade2ea73b9 || b20a5ab0f5fb175750c6bafd4cf12daccf00c738 || 452ae92b99062d2f6a34324eaf705a3b7eac9f8b || 534156dd4ed768e30a43de0036f45dca7c54818f || >=4.14.277 <4.15 || >=4.19.240 <4.20 || >=5.4.190 <5.5 || >=5.10.112 <5.11 || >=5.15.35 <5.16 || >=5.17.2 <5.18 | f4df9d6c8d4e4c818252b0419c2165d66eabd4eb, 52100fd74ad07b53a4666feafff1cd11436362d3, a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964, 3c34fb0bd4a4237592c5ecb5b2e2531900c55774, 4.15, 4.20, 5.5, 5.11, 5.16, 5.18 |
| Linux/Linuxgeneric | 5.18 | Not reported |
Published upstream
Jul 12, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: ax25: Fix refcount imbalance on inbound connections When releasing a socket in ax25_release(), we call netdev_put() to decrease the refcount on the associated ax.25 device. However, the execution path for accepting an incoming connection never calls netdev_hold(). This imbalance leads to refcount errors, and ultimately to kernel crashes. A typical call trace for the above situation will start with one of the following errors: refcount_t: decrement hit 0; leaking memory. refcount_t: underflow; use-after-free. And will then have a trace like: Call Trace: <TASK> ? show_regs+0x64/0x70 ? __warn+0x83/0x120 ? refcount_warn_saturate+0xb2/0x100 ? report_bug+0x158/0x190 ? prb_read_valid+0x20/0x30 ? handle_bug+0x3e/0x70 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? refcount_warn_saturate+0xb2/0x100 ? refcount_warn_saturate+0xb2/0x100 ax25_release+0x2ad/0x360 __sock_release+0x35/0xa0 sock_close+0x19/0x20 [...] On reboot (or any attempt to remove the interface), the kernel gets stuck in an infinite loop: unregister_netdevice: waiting for ax0 to become free. Usage count = 0 This patch corrects these issues by ensuring that we call netdev_hold() and ax25_dev_hold() for new connections in ax25_accept(). This makes the logic leading to ax25_accept() match the logic for ax25_bind(): in both cases we increment the refcount, which is ultimately decremented in ax25_release().
Quoted source text, attributed separately from HOL analysis.