VulnerabilityPublished 25 Jul 2026Updated 6 Nov 2026

CVE-2026-64294: Linux kernel · mm: do file ownership checks with the proper mount idmap

Affects Linux kernelSource CVE Database V5

Compare

Not known to be exploited · fixed in e187bc02f8fa4226d62814592cf064ee4557c470 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:51 UTC

Severity

Low

Rated Low 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, 2026-11-06.

Patch

Available – fixed in e187bc02f8fa4226d62814592cf064ee4557c470, b2f3d94ea310bea9d36d53e9d9b3f45e86c1d893, 8344bdf0629457e532797b42d9d2bbf2a2900bbf +4

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 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 6 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 ≥ 9caccd41541a6f7d6279928d9f971f6642c361af, < e187bc02f8fa4226d62814592cf064ee4557c470	Fixed in e187bc02f8fa4226d62814592cf064ee4557c470
LinuxLinux	Affected ≥ 9caccd41541a6f7d6279928d9f971f6642c361af, < b2f3d94ea310bea9d36d53e9d9b3f45e86c1d893	Fixed in b2f3d94ea310bea9d36d53e9d9b3f45e86c1d893
LinuxLinux	Affected ≥ 9caccd41541a6f7d6279928d9f971f6642c361af, < 8344bdf0629457e532797b42d9d2bbf2a2900bbf	Fixed in 8344bdf0629457e532797b42d9d2bbf2a2900bbf
LinuxLinux	Affected ≥ 9caccd41541a6f7d6279928d9f971f6642c361af, < 7368bec565bac3e536cd43579dbde1e715e6ba61	Fixed in 7368bec565bac3e536cd43579dbde1e715e6ba61
LinuxLinux	Affected ≥ 9caccd41541a6f7d6279928d9f971f6642c361af, < 744b23aa430d52f5c8e4dbff7d71496d6643bed2	Fixed in 744b23aa430d52f5c8e4dbff7d71496d6643bed2
LinuxLinux	Affected ≥ 9caccd41541a6f7d6279928d9f971f6642c361af, < 5c942ad7df75925ee166e7f0fb36892d8dde376b	Fixed in 5c942ad7df75925ee166e7f0fb36892d8dde376b

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel. Users and administrators should update to the fixed kernel versions that include the patch identified by the provided commit hashes. No additional mitigation steps are required beyond applying the official fix.

Description

CVE-2026-64294 is a vulnerability in the Linux kernel related to file ownership checks in the memory management subsystem. The issue arises because inode ownership checks for certain system calls (mincore and madvise with MADV_PAGEOUT) were performed using an incorrect mount idmap, leading to improper permission validation in edge cases involving idmapped mounts. This could cause owner_or_capable() checks to fail unexpectedly when the file ownership is translated differently by the idmap. The vulnerability has been fixed by introducing a new function that performs ownership checks with the correct mount idmap semantics.

Impact

The vulnerability can cause incorrect permission checks on files accessed via idmapped mounts, potentially allowing denial of access to legitimate owners or incorrect permission validation. However, in typical cases such as mincore and madvise MADV_PAGEOUT, the impact is usually benign because other permission checks use the correct idmap. The issue mainly affects edge cases involving complex mount and user ID mappings. There is no indication of active exploitation or severe security impact like privilege escalation or data corruption.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2026, 16:51 UTC

Technical details

References

Community reviews

Related threats