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Critical 9.8Published Apr 24, 2026

CVE-2026-31668seg6: separate dst_cache for input and output paths in seg6 lwtunnel

Updated under an hour ago ()

Does this affect you?

It affects Linux and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
Not given
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Linux
NVD analysis
Analyzed
Record last updated
Oct 16, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Linux Linux
linux:linux (from the name)
6c8702c60b88651072460f3f4026c7dfe2521d12 builds before 1dec91d3b1cefb82635761b7812154af3ef46449; from 6c8702c60b88651072460f3f4026c7dfe2521d12 before 750569d6987a0ff46317a4b86eb3907e296287bf; from 6c8702c60b88651072460f3f4026c7dfe2521d12 before 57d0374d14fa667dec6952173b93e7e84486d5c9; from 6c8702c60b88651072460f3f4026c7dfe2521d12 before 84d458018b147176b259347103fccb7e93abd2b1; from 6c8702c60b88651072460f3f4026c7dfe2521d12 before 6305ad032b03d2ea4181b953a66e19a9a6ed053c; from 6c8702c60b88651072460f3f4026c7dfe2521d12 before fb56de5d99218de49d5d43ef3a99e062ecd0f9a1; from 6c8702c60b88651072460f3f4026c7dfe2521d12 before 17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6a; from 6c8702c60b88651072460f3f4026c7dfe2521d12 before c3812651b522fe8437ebb7063b75ddb95b571643
CNA record
linux linux_kernel
linux:linux_kernel
from 4.10.1 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.169; from 6.2 before 6.6.135; from 6.7 before 6.12.82; from 6.13 before 6.18.23; from 6.19 before 6.19.13; 4.10; and 7 more ranges
NVD

References

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The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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