CVE-2026-72137xfrm: nat_keepalive: avoid double free on send error
- 9.8CriticalCVSS base score
- 0.71%Exploitation in 30 daysEPSS · top 46% 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: xfrm: nat_keepalive: avoid double free on send error nat_keepalive_send() frees the keepalive skb whenever the IPv4 or IPv6 send helper reports an error. That cleanup is only correct before the skb is handed to the output path. Once ip_build_and_send_pkt() or ip6_xmit() takes ownership, the networking stack may already have consumed the skb before returning an error, so freeing it again is unsafe. Handle the pre-handoff failure cases inside nat_keepalive_send_ipv4() and nat_keepalive_send_ipv6(), where the caller still owns the skb, and keep nat_keepalive_send() responsible only for family dispatch and the unsupported-family cleanup path.
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 2 days later
· 2 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 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 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)
- 0.71% · top 46% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- affected f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – < d0a4dc7efa825bce60a8da8f7d43c864a159abde
- affected f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – < 5b0c4c916f202b8fd13d12afb6af62b385622f81
- affected f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – < a8a7e6a9ff8a4c1f067694ddbd44be67fdf36693
- affected f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae – < 226f4a490d1a938fc838d8f8c46a4eca864c0d78
- affected 6.11
- unaffected < 6.11
- unaffected 6.12.101 – ≤ 6.12.*
- unaffected 6.18.40 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References4
- https://git.kernel.org/stable/c/d0a4dc7efa825bce60a8da8f7d43c864a159abde (opens in a new tab)
- https://git.kernel.org/stable/c/5b0c4c916f202b8fd13d12afb6af62b385622f81 (opens in a new tab)
- https://git.kernel.org/stable/c/a8a7e6a9ff8a4c1f067694ddbd44be67fdf36693 (opens in a new tab)
- https://git.kernel.org/stable/c/226f4a490d1a938fc838d8f8c46a4eca864c0d78 (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-2026-58895 (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-2026-72137)Record last updated .