CVE-2026-64541net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket
- 9.8CriticalCVSS base score
- 0.56%Exploitation in 30 daysEPSS · top 52% 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/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket smc_cdc_rx_handler() looks up the connection by token under the link group's conns_lock, drops the lock, and then dereferences conn and the smc_sock derived from it, ending in sock_hold(&smc->sk) inside smc_cdc_msg_recv(). No reference is held across the lock release. The only reference pinning the socket while the connection is discoverable in the link group is taken in smc_lgr_register_conn() (sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both under conns_lock. Once the handler drops conns_lock, a concurrent close() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn() can drop that reference and free the smc_sock, so the handler's later sock_hold() runs on freed memory: WARNING: lib/refcount.c:25 at refcount_warn_saturate Workqueue: rxe_wq do_work refcount_warn_saturate (lib/refcount.c:25) smc_cdc_msg_recv (net/smc/smc_cdc.c:430) smc_cdc_rx_handler (net/smc/smc_cdc.c:502) smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445) tasklet_action_common (kernel/softirq.c:938) handle_softirqs (kernel/softirq.c:622) Kernel panic - not syncing: panic_on_warn set Only SMC-R is affected. The SMC-D receive tasklet is stopped by tasklet_kill(&conn->rx_tsklet) in smc_conn_free() before the connection is unregistered, so it cannot run concurrently with the free. Take the socket reference while still holding conns_lock, so the registration reference can no longer be the last one, and drop it once the handler is done.
Timeline
ID reserved
By Linux
- 8 days later
· 8 days later
Published
- 3 months later
· 3 months 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 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.56% · top 52% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < 8de4f665d0febfb92803dece377791a563fc7041
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < 8145b432136285e01091815b48ceb2dae261f262
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < 1951bffbc6493ec34cff3956b29d4bc6606904a6
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < 647b19e5cc145a2f1f685ae8ff3805a17356888c
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < 472e9d7c0d5b03be3ff91ff941f57da822b031bc
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < 3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < ce5aa8084329351086894aa34d77e40301d5bd3d
- affected d7b0e37c1ac152905b18a5b9506179091a35b0b6 – < 9d160b35cc34a2ba8229d07651468a7848325135
- affected 4.18
- unaffected < 4.18
- unaffected 5.10.261 – ≤ 5.10.*
- unaffected 5.15.212 – ≤ 5.15.*
- unaffected 6.1.178 – ≤ 6.1.*
- unaffected 6.6.145 – ≤ 6.6.*
- unaffected 6.12.97 – ≤ 6.12.*
- unaffected 6.18.40 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/8de4f665d0febfb92803dece377791a563fc7041 (opens in a new tab)
- https://git.kernel.org/stable/c/8145b432136285e01091815b48ceb2dae261f262 (opens in a new tab)
- https://git.kernel.org/stable/c/1951bffbc6493ec34cff3956b29d4bc6606904a6 (opens in a new tab)
- https://git.kernel.org/stable/c/647b19e5cc145a2f1f685ae8ff3805a17356888c (opens in a new tab)
- https://git.kernel.org/stable/c/472e9d7c0d5b03be3ff91ff941f57da822b031bc (opens in a new tab)
- https://git.kernel.org/stable/c/3bfb96d9bc6a7ed0b99c7db329cc2e22a28d84bb (opens in a new tab)
- https://git.kernel.org/stable/c/ce5aa8084329351086894aa34d77e40301d5bd3d (opens in a new tab)
- https://git.kernel.org/stable/c/9d160b35cc34a2ba8229d07651468a7848325135 (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-2026-49592 (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-2026-64541)Record last updated .