Vulnerability Description
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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 4.10.1, < 5.10.253 |
References
- https://git.kernel.org/stable/c/17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6aPatch
- https://git.kernel.org/stable/c/1dec91d3b1cefb82635761b7812154af3ef46449Patch
- https://git.kernel.org/stable/c/57d0374d14fa667dec6952173b93e7e84486d5c9Patch
- https://git.kernel.org/stable/c/6305ad032b03d2ea4181b953a66e19a9a6ed053cPatch
- https://git.kernel.org/stable/c/750569d6987a0ff46317a4b86eb3907e296287bfPatch
- https://git.kernel.org/stable/c/84d458018b147176b259347103fccb7e93abd2b1Patch
- https://git.kernel.org/stable/c/c3812651b522fe8437ebb7063b75ddb95b571643Patch
- https://git.kernel.org/stable/c/fb56de5d99218de49d5d43ef3a99e062ecd0f9a1Patch
FAQ
What is CVE-2026-31668?
CVE-2026-31668 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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, sh...
How severe is CVE-2026-31668?
CVE-2026-31668 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-31668?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.