CVE-2026-72137
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.
Affected versions
Linux kernel versions
6.11
and later are affected. Fixed in
6.12.101,
6.18.40,
7.1.5,
7.2-rc4
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-72137?
CVE-2026-72137 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.11 onward and has been patched in 6.12.101, 6.18.40, 7.1.5 and others. CVE-2026-72137 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-72137?
Yes. CVE-2026-72137 has been patched. Fixed versions include 6.12.101, 6.18.40, 7.1.5 and others. If you are running Linux kernel 6.11 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-72137 actively exploited?
No. CVE-2026-72137 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.