CVE-2026-89488openvswitch: Fix CT limit teardown use-after-free
- 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: openvswitch: Fix CT limit teardown use-after-free Packet processing uses CT limit state under RCU, while netns teardown frees that state under ovs_mutex. The CT limit pointer was neither removed from readers nor protected by a grace period, allowing packet processing to dereference the freed state. An unprivileged user can trigger this bug from a user and network namespace, causing a slab-use-after-free in ovs_ct_execute() when the netns is torn down. Publish the CT limit pointer through RCU, remove it before teardown, and wait for readers before freeing its contents. Keep ovs_mutex around individual CT limit updates, and use the RCU read-side lock while GET traverses the RCU-protected limit lists. Netns teardown detaches the RCU-protected CT limit state in the pernet .pre_exit callback while holding ovs_mutex. The pernet core guarantees an RCU grace period between the .pre_exit and .exit callbacks, so the .exit callback completes the teardown without adding any extra synchronization. The netlink command handlers do not need NULL checks because the userspace netlink socket holds an active reference to its network namespace while a request is processed. The per-netns exit path therefore cannot run concurrently with SET, DEL, or GET for that socket's namespace.
Timeline
ID reserved
By Linux
Published
- 38 days later
· 38 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)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < 239f26589a6926db28c436e14f28517581ef1385
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < 3b9369881b403f4cdbb11fa998554382bdcc3d8c
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < 3b41d907400cc1dd1da9555b81dca422b1f44433
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < 680f20d5937fa4d1367c59fe83091b78041015f5
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < bf4aaa7ea2579e24ed7de2e20578a875bebca011
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < e15407c3a8a005324f633cd46cd8fb58042c1157
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < 6a6d36fadb8537d9b79e72c9fa51885ec0c33e10
- affected 11efd5cb04a184eea4f57b68ea63dddd463158d1 – < 403f96c32c9e24600093d7d0c61c17daeedca957
- affected 4.18
- unaffected < 4.18
- unaffected 5.10.270 – ≤ 5.10.*
- unaffected 5.15.221 – ≤ 5.15.*
- unaffected 6.1.188 – ≤ 6.1.*
- unaffected 6.6.157 – ≤ 6.6.*
- unaffected 6.12.110 – ≤ 6.12.*
- unaffected 6.18.51 – ≤ 6.18.*
- unaffected 7.2.4 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/239f26589a6926db28c436e14f28517581ef1385 (opens in a new tab)
- https://git.kernel.org/stable/c/3b9369881b403f4cdbb11fa998554382bdcc3d8c (opens in a new tab)
- https://git.kernel.org/stable/c/3b41d907400cc1dd1da9555b81dca422b1f44433 (opens in a new tab)
- https://git.kernel.org/stable/c/680f20d5937fa4d1367c59fe83091b78041015f5 (opens in a new tab)
- https://git.kernel.org/stable/c/bf4aaa7ea2579e24ed7de2e20578a875bebca011 (opens in a new tab)
- https://git.kernel.org/stable/c/e15407c3a8a005324f633cd46cd8fb58042c1157 (opens in a new tab)
- https://git.kernel.org/stable/c/6a6d36fadb8537d9b79e72c9fa51885ec0c33e10 (opens in a new tab)
- https://git.kernel.org/stable/c/403f96c32c9e24600093d7d0c61c17daeedca957 (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-2026-76394 (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)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-89488)Record last updated .