CVE-2026-31668
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.4% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.4% in the next 30 days (EPSS).
- Severity: 9.8 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.4% · EPSS, next 30 days
- Weakness
- CWE-459
- Record status
- Modified
Affected
- Linux Kernel < 5.10.253
- Linux Kernel < 5.15.203
- Linux Kernel < 6.1.169
- Linux Kernel < 6.6.135
- Linux Kernel < 6.12.82
- Linux Kernel < 6.18.23
- Linux Kernel < 6.19.13
- Linux Kernel 4.10
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-31668.md and follow it. Check whether this project is affected by CVE-2026-31668. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6a
- https://git.kernel.org/stable/c/1dec91d3b1cefb82635761b7812154af3ef46449
- https://git.kernel.org/stable/c/57d0374d14fa667dec6952173b93e7e84486d5c9
- https://git.kernel.org/stable/c/6305ad032b03d2ea4181b953a66e19a9a6ed053c
- https://git.kernel.org/stable/c/750569d6987a0ff46317a4b86eb3907e296287bf
- https://git.kernel.org/stable/c/84d458018b147176b259347103fccb7e93abd2b1
- https://git.kernel.org/stable/c/c3812651b522fe8437ebb7063b75ddb95b571643
- https://git.kernel.org/stable/c/fb56de5d99218de49d5d43ef3a99e062ecd0f9a1
References
- https://git.kernel.org/stable/c/17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6a
- https://git.kernel.org/stable/c/1dec91d3b1cefb82635761b7812154af3ef46449
- https://git.kernel.org/stable/c/57d0374d14fa667dec6952173b93e7e84486d5c9
- https://git.kernel.org/stable/c/6305ad032b03d2ea4181b953a66e19a9a6ed053c
- https://git.kernel.org/stable/c/750569d6987a0ff46317a4b86eb3907e296287bf
- https://git.kernel.org/stable/c/84d458018b147176b259347103fccb7e93abd2b1
- https://git.kernel.org/stable/c/c3812651b522fe8437ebb7063b75ddb95b571643
- https://git.kernel.org/stable/c/fb56de5d99218de49d5d43ef3a99e062ecd0f9a1