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CVE-2026-31431VulnerabilityPublished Updated

linux, linux-aws, linux-aws-fips, linux-bluefield, linux-fips, linux-gcp, linux-gcp-5.4, linux-gcp-fips, linux-ibm

Affects Linux kernelSource GCVE Database

0
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Mentioned vulnerabilities

Exploited in the wild · KEV due 15 May 2026 · public exploit available (Metasploit) · 98% EPSS · fixed in 5.4.0-1162.171~18.04.1 : patch Linux kernel now.

Data as of 4 Nov 2026, 22:22 UTC

Exploitation

Actively exploited

High severity · No CVSS score from NVD or the CNA

KEV deadline
 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS
98.1% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.4.0-1162.171~18.04.1, 5.4.0-1105.110~18.04.1, 5.4.0-1157.167~18.04.1 +11

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 19 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    1 Metasploit module

  4. Exploited in the wild: evidence found.

    Listed in CISA KEV 18 days before disclosure

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

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. , 18 days before disclosure

  2. KEV remediation due

    US federal deadline

    , 4 days before disclosure

  3. CVE published

    on cve.org

    , t = 0

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu Pro 20.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=esm-infra/focalOther threatsAffected
  • <5.4.0-230.250
Fixed in
  • 5.4.0-230.250
Ubuntu Pro 20.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=esm-infra/focalOther threatsAffected
  • <5.4.0-1159.169
Fixed in
  • 5.4.0-1159.169
Ubuntu Pro 20.04 LTSlinux-bluefieldpkg:deb/ubuntu/linux-bluefield?arch=source&distro=esm-infra/focalOther threatsAffected
  • <5.4.0-1118.125
Fixed in
  • 5.4.0-1118.125
Ubuntu Pro 20.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=esm-infra/focalOther threatsAffected
  • <5.4.0-1162.171
Fixed in
  • 5.4.0-1162.171
Ubuntu Pro 20.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=esm-infra/focalOther threatsAffected
  • <5.4.0-1105.110
Fixed in
  • 5.4.0-1105.110
Ubuntu Pro 20.04 LTSlinux-kvmpkg:deb/ubuntu/linux-kvm?arch=source&distro=esm-infra/focalOther threatsAffected
  • <5.4.0-1146.155
Fixed in
  • 5.4.0-1146.155

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

Description

A vulnerability in the Linux kernel's algif_aead module, known as Copy Fail (CVE-2026-31431), improperly handles in-place cryptographic operations. This flaw allows a local attacker to escalate privileges or potentially escape a container. Additional security issues affecting the Cryptographic API, Packet sockets, and TLS protocol were also identified. These vulnerabilities could be exploited to compromise the system. Fixes have been released for multiple Linux kernel versions, including those for various cloud and specialized platforms.

References

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