VulnerabilityPublished 22 Apr 2026Updated 5 Nov 2026

CVE-2026-31458: Linux kernel · mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in bbe03ad3fb9e714191757ca7b41582f930be7be2 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 22:32 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

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, 2026-11-05.

Patch

Available – fixed in bbe03ad3fb9e714191757ca7b41582f930be7be2, aba546061341b56e9ffb37e1eb661a3628b6ec12, 708033c231bd782858f4ddbb46ee874a5a5fbdab +2

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 0ac32b8affb5a384253dbb8339bd2d0e91add0b7, < bbe03ad3fb9e714191757ca7b41582f930be7be2	Fixed in bbe03ad3fb9e714191757ca7b41582f930be7be2
LinuxLinux	Affected ≥ 0ac32b8affb5a384253dbb8339bd2d0e91add0b7, < aba546061341b56e9ffb37e1eb661a3628b6ec12	Fixed in aba546061341b56e9ffb37e1eb661a3628b6ec12
LinuxLinux	Affected ≥ 0ac32b8affb5a384253dbb8339bd2d0e91add0b7, < 708033c231bd782858f4ddbb46ee874a5a5fbdab	Fixed in 708033c231bd782858f4ddbb46ee874a5a5fbdab
LinuxLinux	Affected ≥ 0ac32b8affb5a384253dbb8339bd2d0e91add0b7, < 1e8da792672481d603fa7cd0d815577220a3ee27	Fixed in 1e8da792672481d603fa7cd0d815577220a3ee27
LinuxLinux	Affected ≥ 0ac32b8affb5a384253dbb8339bd2d0e91add0b7, < 1bfe9fb5ed2667fb075682408b776b5273162615	Fixed in 1bfe9fb5ed2667fb075682408b776b5273162615
LinuxLinux	Affected =5.18	Fixed in–

AI-suggested

A fix is available and has been applied in specific Linux kernel commits identified by their hashes. Users should update to a Linux kernel version that includes these fixes. No additional mitigation is indicated or required beyond applying the official patch.

Description

CVE-2026-31458 is a vulnerability in the Linux kernel's DAMON subsystem where multiple sysfs command paths access an array element without verifying the array size. Privileged users can set the number of contexts to zero, causing NULL pointer dereferences when certain commands are executed. This issue has been fixed in specific Linux kernel commits.

Impact

This vulnerability allows privileged users to cause NULL pointer dereferences in the kernel, which can lead to kernel crashes or denial of service. There is no indication of code execution or privilege escalation from the provided data. Exploitation requires privileged access to sysfs interfaces.

Summary

The vulnerability occurs in the Linux kernel's memory management subsystem DAMON (mm/damon/sysfs). Several sysfs commands dereference contexts_arr[0] without checking if contexts->nr equals 1. A privileged user can set nr_contexts to 0 via sysfs while DAMON is running, leading to NULL pointer dereferences when commands like 'update_schemes_stats' or 'update_tuned_intervals' are issued. The root cause is missing validation of contexts->nr before accessing contexts_arr[0]. The flaw is addressed by adding guards at the entry point of damon_sysfs_handle_cmd().

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Nov 2026, 22:32 UTC

Technical details

References

Community reviews

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