Improper Check for Unusual or Exceptional Conditions in Linux kernel - CVE-2026-98303

Vulnerability details

The vulnerability allows a local user to trigger a kernel warning.

The vulnerability exists due to improper checking of unreachable input routes in icmp_route_lookup() when performing reverse-path route lookup for ICMP output. A local user can supply a packet whose source address resolves to an unreachable input route to trigger a kernel warning.

The reverse-path lookup is reached when the forward output route cannot be used. An unreachable input route can be returned when forwarding is disabled.

Affected software

How to mitigate CVE-2026-98303

External References

• https://git.kernel.org/stable/c/06083cea4a3b95f5ebc85312f97d7086e6c9e782
• https://git.kernel.org/stable/c/1af2d87964d87ba7626d96928d68c09158b5a223
• https://git.kernel.org/stable/c/2998147b59c9df0a51477c7a6b3d1f0ba3127dd4
• https://git.kernel.org/stable/c/83aa83f81a8fec30ff5372dee60b2f0561bcb2ca
• https://git.kernel.org/stable/c/cac69c50716c712ef0114837c9427da66066124c
• https://git.kernel.org/stable/c/fda3000147dc96c75ba162f680bec0a9fecf3037

Related Security Bulletins

• Improper Check for Unusual or Exceptional Conditions in Linux kernel ipv4
• Debian update for linux