CVE-2026-31771: Linux kernel · Out-of-bounds Read
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 1 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| 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
- git.kernel.org/stable/c/1e4b738dd0d0f7b237686167706badad9d30649c (opens in a new tab)
- git.kernel.org/stable/c/ac7889b0fe441e4ef892c40b1d002e91f93fa4ae (opens in a new tab)
- git.kernel.org/stable/c/dbc8b8d33c9e19e17e8b8b1361bbb46e2983f5f2 (opens in a new tab)
- git.kernel.org/stable/c/86c8d07a64d553c41e213b52650020010f9ef23e (opens in a new tab)
- git.kernel.org/stable/c/2b2bf47cd75518c36fa2d41380e4a40641cc89cd (opens in a new tab)