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CVE-2026-72137

Updated on 15 Aug 2026

Severity

9.8 Critical severity

Details

CVSS score
9.8
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

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.

Details

Affected product:
Debian 10 ELS
Affected packages:
linux @ 4.19.0

Fixes

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
Debian 13 In Rollout
14 kernels
  • 6.12.85-1
  • 6.12.86-1
  • 6.12.88-1
  • 6.12.74-2
  • 6.12.73-1
  • 6.12.63-1
  • 6.12.69-1
  • 6.12.74-1
  • 6.12.90-1
  • 6.12.90-2
  • 6.12.94-1
  • 6.12.95-1
  • 6.12.96-1
  • 6.12.100-1
Ubuntu 26.04 Released
1 kernel
  • 7.0.0-31.31