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VulnerabilityPublished Updated

CVE-2026-43304: Linux kernel · libceph: define and enforce CEPH_MAX_KEY_LEN

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2026-43304· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in 5.15.0-1111.118~20.04.1 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.15.0-1111.118~20.04.1, 5.15.0-1116.125~20.04.1, 5.15.0-1111.121~20.04.1 +69
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde@7.0.0-1008.8?arch=source&distro=resoluteOther threatsAffected
  • 7.0.0-1003.3 – 7.0.0-1008.8
4 affected builds
Fixed in–
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threatsAffected
  • <6.17.0-40.40
Fixed in
  • 6.17.0-40.40
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1019.19
Fixed in
  • 6.17.0-1019.19
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threatsAffected
  • 6.14.0-1004.4 – 6.17.0-1020.20
16 affected builds
Fixed in–
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1020.22
Fixed in
  • 6.17.0-1020.22

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been released by Ubuntu as part of their Linux kernel security updates (USN-8490-1). Users should update to the fixed kernel versions and reboot their systems to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. Follow the vendor advisory instructions for updating to the specified package versions to fully remediate this vulnerability.

Description

A critical vulnerability in the Linux kernel's Ceph Core library was resolved by enforcing a maximum key length (CEPH_MAX_KEY_LEN) during key decoding. The fix ensures that the key material fits into a fixed-size buffer, preventing invalid key lengths that could lead to security issues. This vulnerability affects multiple specific Linux kernel versions and has a high CVSS score of 9.8, indicating severe impact. The issue has been addressed in updated kernel packages, and users are advised to apply these updates and reboot their systems.

References

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