CVE-2026-74609tipc: read le->link under the node lock in tipc_node_link_down()
- 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: tipc: read le->link under the node lock in tipc_node_link_down() tipc_node_link_down() caches the link pointer before taking n->lock: struct tipc_link *l = le->link; /* unlocked */ if (!l) return; tipc_node_write_lock(n); if (!tipc_link_is_establishing(l)) { /* deref l */ ... tipc_link_reset(l); /* write into l */ if (delete) { kfree(l); le->link = NULL; The delete=true caller frees that very object under n->lock, so the lock does not protect the cached pointer against it: - CPU A, delete=false: tipc_rcv() on TIPC_LINK_DOWN_EVT, or the link supervision timer via tipc_node_timeout(), reads l unlocked and then dereferences it under n->lock; - CPU B, delete=true: netlink TIPC_NL_BEARER_DISABLE -> bearer_disable() -> tipc_node_delete_links() -> tipc_node_link_down(n, bearer_id, true) -> kfree(l). The link is freed with plain kfree(), not kfree_rcu(), and for UDP bearers disable_media() only schedules the asynchronous cleanup_bearer() work, so its synchronize_net() runs after the links are already gone. An in-flight CPU A that has read l therefore dereferences freed memory once B frees it: a use-after-free read in tipc_link_is_establishing(), and a use-after-free write via tipc_link_reset() on the establishing branch. The following trace was captured on 7.2.0-rc5-00284-gaf39eb111ce6: BUG: KASAN: slab-use-after-free in tipc_link_is_establishing (net/tipc/link.c:285) Read of size 4 at addr ffff88802e2aa068 by task swapper/2/0 tipc_link_is_establishing (net/tipc/link.c:285) tipc_node_link_down (net/tipc/node.c:1076) tipc_node_timeout (net/tipc/node.c:843) Allocated by task 9549: tipc_link_create (net/tipc/link.c:490) tipc_node_check_dest (net/tipc/node.c:1279) tipc_disc_rcv (net/tipc/discover.c:252) tipc_udp_recv (net/tipc/udp_media.c:389) Freed by task 9549: tipc_node_link_down (net/tipc/node.c:1084) tipc_node_delete_links (net/tipc/node.c:1320) bearer_disable (net/tipc/bearer.c:414) __tipc_nl_bearer_disable (net/tipc/bearer.c:992) Move the le->link read inside tipc_node_write_lock(), so it is serialised against the kfree() in the delete path. A racing teardown now either has not run yet, and we see a valid link, or has already run, and we see NULL.
Timeline
ID reserved
By Linux
- 7 days later
· 7 days later
Published
- 55 days later
· 55 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 (15 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 73f646cec35477b5099d7e952297cb9e1855be45 – < 2be741ad565c610871a6a95062c12c39da7168fd
- affected 73f646cec35477b5099d7e952297cb9e1855be45 – < 69d209461c110388710e483a130caf051e4fd09a
- affected 73f646cec35477b5099d7e952297cb9e1855be45 – < de017c22135f545ca4e65d1eada22887b64958eb
- affected 73f646cec35477b5099d7e952297cb9e1855be45 – < 47ba70891b10b2feb52462086b7fcd2ad75d3ce3
- affected 73f646cec35477b5099d7e952297cb9e1855be45 – < a714d62513befef37f71f4ae89bb1fe173b65f2e
- affected 73f646cec35477b5099d7e952297cb9e1855be45 – < c3f2347a47754eac690967cfd82cb6d559817b07
- affected 73f646cec35477b5099d7e952297cb9e1855be45 – < 5558a8312452ddb21eff22b1cbd84302ad951944
- affected 73f646cec35477b5099d7e952297cb9e1855be45 – < cba9ccb47e9fa4cc77692fb896cc5ab57a667882
- affected 4.4
- unaffected < 4.4
- unaffected 5.10.265 – ≤ 5.10.*
- unaffected 5.15.216 – ≤ 5.15.*
- unaffected 6.1.183 – ≤ 6.1.*
- unaffected 6.6.152 – ≤ 6.6.*
- unaffected 6.12.104 – ≤ 6.12.*
- unaffected 6.18.45 – ≤ 6.18.*
- unaffected 7.1.9 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/2be741ad565c610871a6a95062c12c39da7168fd (opens in a new tab)
- https://git.kernel.org/stable/c/69d209461c110388710e483a130caf051e4fd09a (opens in a new tab)
- https://git.kernel.org/stable/c/de017c22135f545ca4e65d1eada22887b64958eb (opens in a new tab)
- https://git.kernel.org/stable/c/47ba70891b10b2feb52462086b7fcd2ad75d3ce3 (opens in a new tab)
- https://git.kernel.org/stable/c/a714d62513befef37f71f4ae89bb1fe173b65f2e (opens in a new tab)
- https://git.kernel.org/stable/c/c3f2347a47754eac690967cfd82cb6d559817b07 (opens in a new tab)
- https://git.kernel.org/stable/c/5558a8312452ddb21eff22b1cbd84302ad951944 (opens in a new tab)
- https://git.kernel.org/stable/c/cba9ccb47e9fa4cc77692fb896cc5ab57a667882 (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-2026-64546 (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-2026-74609)Record last updated .