What is CVE-2026-43304?

CVE-2026-43304 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 5.11 onward and patched in 5.15.202, 6.1.165, 6.6.128 and others. CVE-2026-43304 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43304?

CVE-2026-43304 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-2026-43304?

Yes, CVE-2026-43304 has been patched. Fixed versions include 5.15.202, 6.1.165, 6.6.128 and others. If you are running Linux kernel 5.11 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43304 actively exploited?

CVE-2026-43304 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-43304

Critical

In the Linux kernel, the following vulnerability has been resolved: libceph: define and enforce CEPH_MAX_KEY_LEN When decoding the key, verify that the key material would fit into a fixed-size buffer in process_auth_done() and generally has a sane length. The new CEPH_MAX_KEY_LEN check replaces the existing check for a key with no key material which is a) not universal since CEPH_CRYPTO_NONE has to be excluded and b) doesn't provide much value since a smaller than needed key is just as invalid as no key -- this has to be handled elsewhere anyway.

Package Linux Kernel

Published 2026-05-08

Last modified 2026-05-15

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 5.11 and later are affected. Fixed in 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16, 6.19.6, 7.0 and their respective stable series.

Affected from

≥ 5.11

Fixed in

✓ 5.15.202 5.15.x ✓ 6.1.165 6.1.x ✓ 6.6.128 6.6.x ✓ 6.12.75 6.12.x ✓ 6.18.16 6.18.x ✓ 6.19.6 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43304 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/1b275bd49e58752efb83767a5d1aed41356c5e64
Patch
Kernel patch commit
https://git.kernel.org/stable/c/6405e8c680974bb74e2c98d5249fb52c7b12a6c6
Patch
Kernel patch commit
https://git.kernel.org/stable/c/8d745d38c88ecbed95f6b2b39857bf89f35a3244
Patch

7 patch commits total View all on NVD

Details

CVE ID CVE-2026-43304

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-05-08

Modified 2026-05-15

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43304?

CVE-2026-43304 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 5.11 onward and has been patched in 5.15.202, 6.1.165, 6.6.128 and others. CVE-2026-43304 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43304?

CVE-2026-43304 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-2026-43304?

Yes — CVE-2026-43304 has been patched. Fixed versions include 5.15.202, 6.1.165, 6.6.128 and others. If you are running Linux kernel 5.11 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43304 actively exploited?

No — CVE-2026-43304 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.