What is CVE-2026-31637?

CVE-2026-31637 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 2.6.22 onward and patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-31637 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-31637?

CVE-2026-31637 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-2026-31637?

Yes, CVE-2026-31637 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 2.6.22 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-31637 actively exploited?

CVE-2026-31637 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-31637

Critical

In the Linux kernel, the following vulnerability has been resolved: rxrpc: reject undecryptable rxkad response tickets rxkad_decrypt_ticket() decrypts the RXKAD response ticket and then parses the buffer as plaintext without checking whether crypto_skcipher_decrypt() succeeded. A malformed RESPONSE can therefore use a non-block-aligned ticket length, make the decrypt operation fail, and still drive the ticket parser with attacker-controlled bytes. Check the decrypt result and abort the connection with RXKADBADTICKET when ticket decryption fails.

Package Linux Kernel

Published 2026-04-24

Last modified 2026-06-01

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 2.6.22 and later are affected. Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.135, 6.12.82, 6.18.23, 6.19.13, 7.0 and their respective stable series.

Affected from

≥ 2.6.22

Fixed in

✓ 5.10.258 5.10.x ✓ 5.15.209 5.15.x ✓ 6.1.175 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-2026-31637 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/22f6258e7b31dba9bf88dce4e3ee7f0f20072e60
Patch
Kernel patch commit
https://git.kernel.org/stable/c/252157d939d179b5d767cb860ff8fa7f8723b67a
Patch
Kernel patch commit
https://git.kernel.org/stable/c/47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a
Patch

8 patch commits total View all on NVD

Details

CVE ID CVE-2026-31637

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-04-24

Modified 2026-06-01

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-31637?

CVE-2026-31637 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 2.6.22 onward and has been patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-31637 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-31637?

CVE-2026-31637 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-2026-31637?

Yes — CVE-2026-31637 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 2.6.22 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-31637 actively exploited?

No — CVE-2026-31637 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.