CVE-2026-72137: critical vulnerability in Linux
xfrm: nat_keepalive: avoid double free on send error
Published · Updated
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.8epss 0.7%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Linux · LinuxRelated CVEs — Linux
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