- 8.2HighCVSS base score
- 0.60%Exploitation in 30 daysEPSS · top 51% 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: mptcp: fix uninitialized local_id in syncookie MP_JOIN reconstruction mptcp_token_join_cookie_init_state() restores remote_nonce, local_nonce, backup, join_id, token and msk from the saved cookie entry when rebuilding the request socket for a MP_JOIN 4th-ACK handled under SYN cookies, but it does not restore local_id, even though the SYN path saved it. subflow_ulp_clone() then reads that uninitialized field and stores it as the joined subflow's address-ID. Because the request-sock slab is SLAB_TYPESAFE_BY_RCU and not zeroed on allocation, the value is the stale byte of a previously freed request socket, which an off-path peer can influence by sending concurrent MP_JOIN SYNs. This corrupts the path manager's id-based subflow bookkeeping for the connection. Restore subflow_req->local_id from the cookie entry, as done for the other fields.
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 | High8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
| NVDNVD · Received | 3.1 | High8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
- EPSS (exploitation in 30 days)
- 0.60% · top 51% of all CVEs (11 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.2.
Affected products
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < 4534e0eead692bb069ad1e6a5a245fc2e2078300
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < 63cacb05e51a1c6e1349d2e593d00fd6ef43def4
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < 954b5ea836eb118d188975ced803448537ab8479
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < 9df36a4846375a9b75bf42d77bfed216b0f366f9
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < 64f2c5dd49b956a542c8c02b8dad5d262a462bba
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < 51887ccd88791ddaa8755a7c614fda031ecf7982
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < bf19d166337c6488b39cb03eeeffb30a941d6326
- affected 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 – < b878dfdd12d7a5b8722a78d35e313506140ca3d9
- affected 5.9
- unaffected < 5.9
- 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 6.12.109 – ≤ 6.12.*
- unaffected 6.18.50 – ≤ 6.18.*
- unaffected 7.2.4 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
8
- https://git.kernel.org/stable/c/4534e0eead692bb069ad1e6a5a245fc2e2078300 (opens in a new tab)
- https://git.kernel.org/stable/c/63cacb05e51a1c6e1349d2e593d00fd6ef43def4 (opens in a new tab)
- https://git.kernel.org/stable/c/954b5ea836eb118d188975ced803448537ab8479 (opens in a new tab)
- https://git.kernel.org/stable/c/9df36a4846375a9b75bf42d77bfed216b0f366f9 (opens in a new tab)
- https://git.kernel.org/stable/c/64f2c5dd49b956a542c8c02b8dad5d262a462bba (opens in a new tab)
- https://git.kernel.org/stable/c/51887ccd88791ddaa8755a7c614fda031ecf7982 (opens in a new tab)
- https://git.kernel.org/stable/c/bf19d166337c6488b39cb03eeeffb30a941d6326 (opens in a new tab)
- https://git.kernel.org/stable/c/b878dfdd12d7a5b8722a78d35e313506140ca3d9 (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-2026-76465 (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-2026-89554)Record last updated .