Answer in brief
CVE-2021-47559 records a High severity (CVSS 7.5) vulnerability in net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk(). 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.
CVSS is 7.5. 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.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=cb9d43f6775457cac75544bc4197f26ac2b6f294 <c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff || >=cb9d43f6775457cac75544bc4197f26ac2b6f294 <bb851d0fb02547d03cd40106b5f2391c4fed6ed1 || >=cb9d43f6775457cac75544bc4197f26ac2b6f294 <587acad41f1bc48e16f42bb2aca63bf323380be8 | c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff, bb851d0fb02547d03cd40106b5f2391c4fed6ed1, 587acad41f1bc48e16f42bb2aca63bf323380be8 |
| Linux/Linuxgeneric | 4.18 | Not reported |
Published upstream
May 24, 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 4, 2026
In the Linux kernel, the following vulnerability has been resolved: net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk() Coverity reports a possible NULL dereferencing problem: in smc_vlan_by_tcpsk(): 6. returned_null: netdev_lower_get_next returns NULL (checked 29 out of 30 times). 7. var_assigned: Assigning: ndev = NULL return value from netdev_lower_get_next. 1623 ndev = (struct net_device *)netdev_lower_get_next(ndev, &lower); CID 1468509 (#1 of 1): Dereference null return value (NULL_RETURNS) 8. dereference: Dereferencing a pointer that might be NULL ndev when calling is_vlan_dev. 1624 if (is_vlan_dev(ndev)) { Remove the manual implementation and use netdev_walk_all_lower_dev() to iterate over the lower devices. While on it remove an obsolete function parameter comment.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2021-47559 records a High severity (CVSS 7.5) vulnerability in net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk(). 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.
CVSS is 7.5. 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.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=cb9d43f6775457cac75544bc4197f26ac2b6f294 <c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff || >=cb9d43f6775457cac75544bc4197f26ac2b6f294 <bb851d0fb02547d03cd40106b5f2391c4fed6ed1 || >=cb9d43f6775457cac75544bc4197f26ac2b6f294 <587acad41f1bc48e16f42bb2aca63bf323380be8 | c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff, bb851d0fb02547d03cd40106b5f2391c4fed6ed1, 587acad41f1bc48e16f42bb2aca63bf323380be8 |
| Linux/Linuxgeneric | 4.18 | Not reported |
Published upstream
May 24, 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 4, 2026
In the Linux kernel, the following vulnerability has been resolved: net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk() Coverity reports a possible NULL dereferencing problem: in smc_vlan_by_tcpsk(): 6. returned_null: netdev_lower_get_next returns NULL (checked 29 out of 30 times). 7. var_assigned: Assigning: ndev = NULL return value from netdev_lower_get_next. 1623 ndev = (struct net_device *)netdev_lower_get_next(ndev, &lower); CID 1468509 (#1 of 1): Dereference null return value (NULL_RETURNS) 8. dereference: Dereferencing a pointer that might be NULL ndev when calling is_vlan_dev. 1624 if (is_vlan_dev(ndev)) { Remove the manual implementation and use netdev_walk_all_lower_dev() to iterate over the lower devices. While on it remove an obsolete function parameter comment.
Quoted source text, attributed separately from HOL analysis.