Answer in brief
CVE-2025-40297 records a High severity (CVSS 7.8) vulnerability in net: bridge: fix use-after-free due to MST port state bypass. 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 7.8. 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 | >=ec7328b59176227216c461601c6bd0e922232a9b <e19085b2a86addccff33ab8536fc67ebd9d52198 || >=ec7328b59176227216c461601c6bd0e922232a9b <3b60ce334c1ce8b3fad7e02dcd5ed9f6646477c8 || >=ec7328b59176227216c461601c6bd0e922232a9b <bf3843183bc3158e5821b46f330c438ae9bd6ddb || >=ec7328b59176227216c461601c6bd0e922232a9b <991fbe1680cd41a5f97c92cd3a3496315df36e4b || >=ec7328b59176227216c461601c6bd0e922232a9b <8dca36978aa80bab9d4da130c211db75c9e00048 | e19085b2a86addccff33ab8536fc67ebd9d52198, 3b60ce334c1ce8b3fad7e02dcd5ed9f6646477c8, bf3843183bc3158e5821b46f330c438ae9bd6ddb, 991fbe1680cd41a5f97c92cd3a3496315df36e4b, 8dca36978aa80bab9d4da130c211db75c9e00048 |
| Linux/Linuxgeneric | 5.18 | Not reported |
Published upstream
Dec 8, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 15, 2026
In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix use-after-free due to MST port state bypass syzbot reported[1] a use-after-free when deleting an expired fdb. It is due to a race condition between learning still happening and a port being deleted, after all its fdbs have been flushed. The port's state has been toggled to disabled so no learning should happen at that time, but if we have MST enabled, it will bypass the port's state, that together with VLAN filtering disabled can lead to fdb learning at a time when it shouldn't happen while the port is being deleted. VLAN filtering must be disabled because we flush the port VLANs when it's being deleted which will stop learning. This fix adds a check for the port's vlan group which is initialized to NULL when the port is getting deleted, that avoids the port state bypass. When MST is enabled there would be a minimal new overhead in the fast-path because the port's vlan group pointer is cache-hot. [1] https://syzkaller.appspot.com/bug?extid=dd280197f0f7ab3917be
Quoted source text, attributed separately from HOL analysis.