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VulnerabilityPublished Updated

CVE-2026-31533: Linux kernel · net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2026-31533· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in 5.4.0-1160.170~18.04.1 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.4.0-1160.170~18.04.1, 5.4.0-1163.169~18.04.1, 5.4.0-1162.171~18.04.1 +96
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 23 Apr 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-nvidiapkg:deb/ubuntu/linux-nvidia@7.0.0-1006.6?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1006.6
Fixed in
  • 7.0.0-1006.6
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-29.29?arch=source&distro=questingOther threatsAffected
  • <6.17.0-29.29
Fixed in
  • 6.17.0-29.29
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1015.15?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1015.15
Fixed in
  • 6.17.0-1015.15
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1015.15?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1015.15
Fixed in
  • 6.17.0-1015.15
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@6.17.0-1018.19?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1018.19
Fixed in
  • 6.17.0-1018.19

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 should be applied promptly. The vendor advisory from Ubuntu confirms that this issue is fixed in updated Linux kernel packages. After applying the update, a system reboot is required. Due to ABI changes, third-party kernel modules must be recompiled and reinstalled. Follow vendor instructions for updating to the fixed kernel versions.

Description

A use-after-free vulnerability in the Linux kernel's TLS encryption code (tls_do_encryption) was fixed. The flaw involves double cleanup of encryption-related data structures when handling -EBUSY errors, leading to memory corruption and potential use-after-free conditions. This vulnerability affects specific Linux kernel versions and has a high CVSS score of 9.8. A patch is available and should be applied to mitigate the issue.

References

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