CVE-2026-52906

7.7 HIGH 0.1% exploit odds Fix listed Other OS & kernel

What it is

In the Linux kernel, the following vulnerability has been resolved: 9p: fix access mode flags being ORed instead of replaced Since commit 1f3e4142c0eb ("9p: convert to the new mount API"), v9fs_apply_options() applies parsed mount flags with |= onto flags already set by v9fs_session_init(). For 9P2000.L, session_init sets V9FS_ACCESS_CLIENT as the default, so when the user mounts with "access=user", both bits end up set. Access mode checks compare against exact values, so having both bits set matches neither mode. This causes v9fs_fid_lookup() to fall through to the default switch case, using INVALID_UID (nobody/65534) instead of current_fsuid() for all fid lookups. Root is then unable to chown or perform other privileged operations. Fix by clearing the access mask before applying the user's choice.

At a glance

Exploitability: Can be exploited locally on the machine without logging in. High risk of data exposure, data tampering.
Exploit odds: 0.1% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-09 14:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-07-23 08:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.1% in the next 30 days (EPSS).
Severity: 7.7 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-06-09 14:16 UTC
Last modified: 2026-07-23 08:10 UTC
Exploit probability: 0.1% · EPSS, next 30 days
Record status: Analyzed

Affected

Linux Kernel < 7.0.4

Attack profile CVSS 3.1 · 7.7

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Raw vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2026-52906.md and follow it. Check whether this project is affected by CVE-2026-52906. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record