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VulnerabilityPublished Updated

CVE-2026-31771: Linux kernel · Out-of-bounds Read

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.1 High · fixed in dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2 : patch Linux kernel soon.

Data as of 26 Oct 2026, 21:02 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2, ac7889b0fe441e4ef892c40b1d002e91f93fa4ae, 86c8d07a64d553c41e213b52650020010f9ef23e +2
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 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
LinuxLinuxAffected
  • ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2
Fixed in
  • dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2
LinuxLinuxAffected
  • ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < ac7889b0fe441e4ef892c40b1d002e91f93fa4ae
Fixed in
  • ac7889b0fe441e4ef892c40b1d002e91f93fa4ae
LinuxLinuxAffected
  • ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < 86c8d07a64d553c41e213b52650020010f9ef23e
Fixed in
  • 86c8d07a64d553c41e213b52650020010f9ef23e
LinuxLinuxAffected
  • ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < 2b2bf47cd75518c36fa2d41380e4a40641cc89cd
Fixed in
  • 2b2bf47cd75518c36fa2d41380e4a40641cc89cd
LinuxLinuxAffected
  • ≥ 2f20216c1d6fe17c1a224f658be0dc6fab2269c7, < 1e4b738dd0d0f7b237686167706badad9d30649c
Fixed in
  • 1e4b738dd0d0f7b237686167706badad9d30649c
LinuxLinuxAffected
  • =5.10
Fixed in–

AI-suggested

A fix for this vulnerability is available and has been applied in the Linux kernel in the specified commits. Users and administrators should update to a Linux kernel version that includes these fixes. Since this is not a cloud service, manual patching is required. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-31771 is a high-severity vulnerability in the Linux kernel's Bluetooth subsystem. It involves improper handling of HCI event packets where a short event frame can reach a memory copy function before bounds checking, potentially leading to out-of-bounds access. The issue was addressed by moving wake reason storage into validated event handlers after event-length validation and enforcing locking contracts to prevent improper access.

References

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