PT-2026-35020 · Linux · Linux

Published 2026-04-24 · Updated 2026-04-24 · CVE-2026-31668

Mitre

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

seg6: separate dst cache for input and output paths in seg6 lwtunnel

The seg6 lwtunnel uses a single dst cache per encap route, shared between seg6 input core() and seg6 output core(). These two paths can perform the post-encap SID lookup in different routing contexts (e.g., ip rules matching on the ingress interface, or VRF table separation). Whichever path runs first populates the cache, and the other reuses it blindly, bypassing its own lookup.

Fix this by splitting the cache into cache input and cache output, so each path maintains its own cached dst independently.

Related Identifiers

CVE-2026-31668

Affected Products

Linux

References · 9

• https://nvd.nist.gov/vuln/detail/CVE-2026-31668 · Security Note
• https://git.kernel.org/stable/c/57d0374d14fa667dec6952173b93e7e84486d5c9 · Note
• https://git.kernel.org/stable/c/750569d6987a0ff46317a4b86eb3907e296287bf · Note
• https://git.kernel.org/stable/c/6305ad032b03d2ea4181b953a66e19a9a6ed053c · Note
• https://git.kernel.org/stable/c/84d458018b147176b259347103fccb7e93abd2b1 · Note
• https://git.kernel.org/stable/c/c3812651b522fe8437ebb7063b75ddb95b571643 · Note
• https://git.kernel.org/stable/c/1dec91d3b1cefb82635761b7812154af3ef46449 · Note
• https://git.kernel.org/stable/c/fb56de5d99218de49d5d43ef3a99e062ecd0f9a1 · Note
• https://git.kernel.org/stable/c/17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6a · Note