CVE-2026-31431: linux-aws-5.4, linux-hwe-5.4 vulnerabilities
Affects Linux kernelSource GCVE Database
Mentioned vulnerabilities
Exploited in the wild · KEV due 15 May 2026 · public exploit available (Metasploit) · 98% EPSS · fixed in 5.4.0-1160.170~18.04.1 : patch Linux kernel now.
Data as of 4 Nov 2026, 22:11 UTC
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 5.4.0-1160.170~18.04.1, 5.4.0-231.251~18.04.1
Exploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 4 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 34 days before disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
Added to CISA KEV (opens in a new tab)
exploitation confirmed
, 34 days before disclosure
KEV remediation due
US federal deadline
, 20 days before disclosure
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 the Ubuntu to 5.4.0-1160.170~18.04.1 (linux-aws-5.4 package) or 5.4.0-231.251~18.04.1 (linux-hwe-5.4 package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu Pro 18.04 LTSlinux-aws-5.4pkg:deb/ubuntu/linux-aws-5.4?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in
|
Ubuntu Pro 18.04 LTSlinux-hwe-5.4pkg:deb/ubuntu/linux-hwe-5.4?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
Multiple security vulnerabilities were discovered in the Linux kernel versions used in linux-aws-5.4 and linux-hwe-5.4. These include flaws in the algif_aead cryptographic module and socket buffer handling, which could allow a local attacker to escalate privileges or escape container environments. The vulnerabilities affect several subsystems including Cryptographic API, Packet sockets, RDS protocol, and TLS protocol. Fixes are available in updated kernel versions and should be applied promptly.
References
- ubuntu.com/security/notices/USN-8392-1 (opens in a new tab)
- ubuntu.com/security/CVE-2026-31431 (opens in a new tab)
- ubuntu.com/security/CVE-2026-31504 (opens in a new tab)
- ubuntu.com/security/CVE-2026-31533 (opens in a new tab)
- ubuntu.com/security/CVE-2026-43033 (opens in a new tab)
- ubuntu.com/security/CVE-2026-43077 (opens in a new tab)
- ubuntu.com/security/CVE-2026-43078 (opens in a new tab)
- ubuntu.com/security/CVE-2026-43284 (opens in a new tab)
- ubuntu.com/security/CVE-2026-43494 (opens in a new tab)
- ubuntu.com/security/CVE-2026-43500 (opens in a new tab)
- ubuntu.com/security/CVE-2026-46028 (opens in a new tab)