CVE-2026-80848: xfrm: espintcp: fix UAF during close
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-08 00:03 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
In the Linux kernel, the following vulnerability has been resolved: xfrm: espintcp: fix UAF during close ZDI reported and analyzed a race condition during close for espintcp sockets: espintcp_close() frees emsg->skb via kfree_skb() without holding any socket lock. Concurrently, the xfrm_trans_reinject work queue invokes esp_output_tcp_finish() -> espintcp_push_skb() -> espintcp_push_msgs() -> skb_send_sock_locked(), which reads the same skb as a data source. Fix this by adding a synchronize_rcu() call after resetting sk_prot, since esp_output_tcp_finish() runs under RCU and won’t use a socket with sk_prot == &tcp_prot. Simply taking the socket lock in espintcp_close() could lead to leaks, if esp_output_tcp_finish() re-adds an skb in the slot we just freed. After this, the existing barrier() is no longer needed.
Description quoted from the CVE record (assigned by Linux, published 2026-09-04).
How it can be exploited
Public exploit evidence (Exploit Observer)
Exploit Observer found 2 research write-ups naming this CVE.
See all 10 references on Exploit Observer
Live scores
- EPSS
- 0.002
low predicted chance of attack - VEDAS
- 0.967
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Linux | from e27cca96cd68 before 29121c5e6591 (git commit) from e27cca96cd68 before ed5d9102190c (git commit) from e27cca96cd68 before 4bc0dfa28dca (git commit) from e27cca96cd68 before ff8dd7a932f3 (git commit) from e27cca96cd68 before 4b31a875693c (git commit) from e27cca96cd68 before 24efebecf415 (git commit) from e27cca96cd68 before eb3bbf29c723 (git commit) from e27cca96cd68 before 54b41ad14da9 (git commit) and 1 more ranges | Not stated |
| Linux | version 5.6 | 0 is not affected (up to 5.6); 5.10.269 is not affected; 5.15.220 is not affected; 6.1.187 is not affected |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Other references
- https://git.kernel.org/stable/c/29121c5e6591da527e8e36ddac7120dc527f574d
- https://git.kernel.org/stable/c/ed5d9102190c45fc70121c036b0626b740040b75
- https://git.kernel.org/stable/c/4bc0dfa28dca6fc0084203732695968049c44072
- https://git.kernel.org/stable/c/ff8dd7a932f34409a56e1b91a1219340f17457e9
- https://git.kernel.org/stable/c/4b31a875693c480c611519faca46216514e3e052
- https://git.kernel.org/stable/c/24efebecf415ba264adba0f0491cec436463a14f
- https://git.kernel.org/stable/c/eb3bbf29c723fe75c0eb92be14f0ec92971fe272
- https://git.kernel.org/stable/c/54b41ad14da9a981131ab6e4d3f79321a503ea5d
- https://git.kernel.org/stable/c/deb232e884877bf10b4ce2580909eedec986c284
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
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