PT-2026-61309 · Linux · Linux Kernel

CVE-2026-63992 · Published 2026-07-19 · Updated 2026-07-19

Positive Technologies (AI Summary)

CVSS v3.1

9.1

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An out-of-bound access occurs in the iptunnel pmtud check icmp() function when it is called while the skb transport header is not set. This happens because the system incorrectly assumes the presence of a transport header, leading to an invalid memory access using the value 65535. The issue is resolved by accessing the ICMP header based on the IPv4 network header and verifying that the icmp->type is present in the skb linear part.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Related Identifiers

CVE-2026-63992

Affected Products

Linux Kernel

References · 11

• https://nvd.nist.gov/vuln/detail/CVE-2026-63992 · Security Note
• https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4 · Note
• https://twitter.com/CVEnew/status/2078861459774210364 · Twitter Post
• https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c · Note
• https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c · Note
• https://twitter.com/infoflowcloud/status/2078862755847708986 · Twitter Post
• https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93 · Note
• https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d · Note
• https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec · Note
• https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7 · Note
• https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e · Note