CVE-2026-99117net: bridge: mcast: don't truncate the port group walk on teardown
- 7.8HighCVSS base score
- 0.13%Exploitation in 30 daysEPSS · top 98% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: net: bridge: mcast: don't truncate the port group walk on teardown __br_multicast_disable_port_ctx() and br_multicast_del_port() walk port->mglist with hlist_for_each_entry_safe(). However, br_multicast_find_del_pg() can also delete other entries from the same list through br_multicast_fwd_src_remove() or __fwd_del_star_excl(). If such an entry is the iterator's saved next node, hlist_del_init() clears its ->next and terminates the walk early. The reproducer triggers this in both teardown walks, leaving port groups in the bridge mdb with a dangling ->key.port after del_nbp() frees the port: BUG: KASAN: slab-use-after-free in __mdb_fill_info+0x1191/0x1320 __mdb_fill_info+0x1191/0x1320 br_mdb_dump+0x594/0xe40 rtnl_mdb_dump+0x1cf/0x5d0 Use hlist_del_init_rcu() to unlink the group while preserving ->next. br_multicast_del_pg() and the teardown walks run under br->multicast_lock. The GC worker must acquire the same lock before detaching the group for destruction, so the node remains alive while the walk uses the preserved pointer. Preserving ->next means a walk can now reach a group that an earlier iteration already deleted as a side effect. That group is off mp->ports, so br_multicast_find_del_pg() would fall through its port scan and hit the trailing WARN_ON(1). Skip such groups at the top of that helper: a port group is put on port->mglist when it is created and only unlinked when it is deleted, so hlist_unhashed() identifies exactly this case.
Timeline
ID reserved
By Linux
- 33 days later
· 33 days later
Published
- 3 days later
· 3 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.13% · top 98% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < be331b23c650de9518f8266b901d8abb9b36af77
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < ab836d56ff43f2e7927e88c83cd02c47a98a672e
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < 025c25ad73323c7dc5af4ee97fe0a2c0b3c177c8
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < b0db9f4ff402becff710ab27dbd9f6fe4850b47e
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < e69d4927dacd6ddaff09777a89efc0d3143d3b0d
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < 8243d587a081e790ad96e80d48eef44d9f7ef005
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < b45e8c24608c992d1e2cea047eb5bcbfa537f86b
- affected b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2 – < 5a3f7a683aee56e1f15c9d53041f3236767eaae7
- affected 5.10
- unaffected < 5.10
- unaffected 5.10.273 – ≤ 5.10.*
- unaffected 5.15.224 – ≤ 5.15.*
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.161 – ≤ 6.6.*
- unaffected 6.12.115 – ≤ 6.12.*
- unaffected 6.18.59 – ≤ 6.18.*
- unaffected 7.2.13 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/be331b23c650de9518f8266b901d8abb9b36af77 (opens in a new tab)
- https://git.kernel.org/stable/c/ab836d56ff43f2e7927e88c83cd02c47a98a672e (opens in a new tab)
- https://git.kernel.org/stable/c/025c25ad73323c7dc5af4ee97fe0a2c0b3c177c8 (opens in a new tab)
- https://git.kernel.org/stable/c/b0db9f4ff402becff710ab27dbd9f6fe4850b47e (opens in a new tab)
- https://git.kernel.org/stable/c/e69d4927dacd6ddaff09777a89efc0d3143d3b0d (opens in a new tab)
- https://git.kernel.org/stable/c/8243d587a081e790ad96e80d48eef44d9f7ef005 (opens in a new tab)
- https://git.kernel.org/stable/c/b45e8c24608c992d1e2cea047eb5bcbfa537f86b (opens in a new tab)
- https://git.kernel.org/stable/c/5a3f7a683aee56e1f15c9d53041f3236767eaae7 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-112017 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-99117)Record last updated .