{"cve":"CVE-2025-40297","nvd":{"published":"2025-12-08T01:16:01.813","modified":"2026-10-15T22:19:07.277","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: fix use-after-free due to MST port state bypass\n\nsyzbot reported[1] a use-after-free when deleting an expired fdb. It is\ndue to a race condition between learning still happening and a port being\ndeleted, after all its fdbs have been flushed. The port's state has been\ntoggled to disabled so no learning should happen at that time, but if we\nhave MST enabled, it will bypass the port's state, that together with VLAN\nfiltering disabled can lead to fdb learning at a time when it shouldn't\nhappen while the port is being deleted. VLAN filtering must be disabled\nbecause we flush the port VLANs when it's being deleted which will stop\nlearning. This fix adds a check for the port's vlan group which is\ninitialized to NULL when the port is getting deleted, that avoids the port\nstate bypass. When MST is enabled there would be a minimal new overhead\nin the fast-path because the port's vlan group pointer is cache-hot.\n\n[1] https://syzkaller.appspot.com/bug?extid=dd280197f0f7ab3917be","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/3b60ce334c1ce8b3fad7e02dcd5ed9f6646477c8","https://git.kernel.org/stable/c/8dca36978aa80bab9d4da130c211db75c9e00048","https://git.kernel.org/stable/c/991fbe1680cd41a5f97c92cd3a3496315df36e4b","https://git.kernel.org/stable/c/bf3843183bc3158e5821b46f330c438ae9bd6ddb","https://git.kernel.org/stable/c/e19085b2a86addccff33ab8536fc67ebd9d52198"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:16:40.427100871+00:00"},"epss":{"cve":"CVE-2025-40297","score":0.00157,"percentile":0.04821,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}