What is CVE-2026-31668?

CVE-2026-31668 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 4.10 onward and patched in 5.10.253, 5.15.203, 6.1.169 and others. CVE-2026-31668 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-31668?

CVE-2026-31668 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-31668?

Yes, CVE-2026-31668 has been patched. Fixed versions include 5.10.253, 5.15.203, 6.1.169 and others. If you are running Linux kernel 4.10 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-31668 actively exploited?

CVE-2026-31668 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-31668

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, 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.

Package Linux Kernel

Published 2026-04-24

Last modified 2026-04-27

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 4.10 and later are affected. Fixed in 5.10.253, 5.15.203, 6.1.169, 6.6.135, 6.12.82, 6.18.23, 6.19.13, 7.0 and their respective stable series.

Affected from

≥ 4.10

Fixed in

✓ 5.10.253 5.10.x ✓ 5.15.203 5.15.x ✓ 6.1.169 6.1.x ✓ 6.6.135 6.6.x ✓ 6.12.82 6.12.x ✓ 6.18.23 6.18.x ✓ 6.19.13 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-31668 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6a
Patch
Kernel patch commit
https://git.kernel.org/stable/c/1dec91d3b1cefb82635761b7812154af3ef46449
Patch
Kernel patch commit
https://git.kernel.org/stable/c/57d0374d14fa667dec6952173b93e7e84486d5c9
Patch

8 patch commits total View all on NVD

Details

CVE ID CVE-2026-31668

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-04-24

Modified 2026-04-27

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-31668?

CVE-2026-31668 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 4.10 onward and has been patched in 5.10.253, 5.15.203, 6.1.169 and others. CVE-2026-31668 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-31668?

CVE-2026-31668 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-31668?

Yes — CVE-2026-31668 has been patched. Fixed versions include 5.10.253, 5.15.203, 6.1.169 and others. If you are running Linux kernel 4.10 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-31668 actively exploited?

No — CVE-2026-31668 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.