CVE-2026-63992

Summary

In the Linux kernel, the following vulnerability has been resolved:

tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()

In some cases, iptunnel_pmtud_check_icmp() can be called while skb transport header is not set.

This triggers an out-of-bound access, because (typeof(skb->transport_header))~0U is 65535.

Access the icmp header based on IPv4 network header, after making sure icmp->type is present in skb linear part.

Note that iptunnel_pmtud_check_icmpv6()) is fine.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 5a92cb45e34749865d03daf8d3500f77b5f6644caffected
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < c7b7ec3e69e673c0d6b57f74d21da50c485c598eaffected
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 7f4f7efe7f30edd29c4988de01728bf2398217e4affected
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < e917d0c69f01af2bb4fbea2b66d560a53b3ac7ecaffected
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < a096b6e34f602950af9a2b0856cd93a5f4c276d7affected
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 43368636c663cff6e59dde93cf4b8e43ac28eb93affected
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < cb549df9ce4ee15c9d5b19ddab12cf2128e4313caffected
LinuxLinux4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 509323077ef79a26ba0c60bb556e45c12c398b2daffected
LinuxLinux5.9affected
LinuxLinux0 < 5.9unaffected
LinuxLinux5.10.259 <= 5.10.*unaffected
LinuxLinux5.15.210 <= 5.15.*unaffected
LinuxLinux6.1.176 <= 6.1.*unaffected
LinuxLinux6.6.143 <= 6.6.*unaffected
LinuxLinux6.12.93 <= 6.12.*unaffected
LinuxLinux6.18.35 <= 6.18.*unaffected
LinuxLinux7.0.12 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References