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VulnerabilityPublished Updated

CVE-2026-31512: Linux kernel · Bluetooth: L2CAP: Validate PDU length before reading SDU length in

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 5.5 Medium · patch available : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 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

Affected software

ProductAffectedFixed in
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threatsAffected
  • 6.14.0-15.15 – 6.17.0-40.40
20 affected builds
Fixed in–
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threatsAffected
  • 6.14.0-1005.5 – 6.17.0-1019.19
17 affected builds
Fixed in–
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
  • 6.14.0-1006.6 – 6.17.0-1020.22
17 affected builds
Fixed in–
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?arch=source&distro=questingOther threatsAffected
  • 6.14.0-1005.5 – 6.17.0-1018.18
16 affected builds
Fixed in–

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

AI-suggested

A vendor-provided patch is available and should be applied to affected linux-aws kernel versions. The Ubuntu security advisory USN-8567-1 confirms the fix. Systems running the affected versions should be updated to the patched kernel releases to remediate this vulnerability.

Description

A vulnerability in the Linux kernel's Bluetooth L2CAP implementation (CVE-2026-31512) involves improper validation of the PDU length before reading the SDU length in the l2cap_ecred_data_rcv() function. This can lead to reading beyond the valid data buffer when the skb length is less than 2 bytes. The issue has been fixed by applying proper validation similar to the existing ERTM reassembly path. The vulnerability affects specific linux-aws kernel versions and has a medium severity score of 5.5. A patch is available from the vendor.

References

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