CVE Catalog

CVE-2025-68788

Low risk· EPSS 7%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.17%

7th percentile - higher than 7% of all known CVEs

Summary

A vulnerability in the Linux kernel's fsnotify mechanism allowed generating ACCESS/MODIFY events for special files (e.g., /dev/null) during read/write by other users. The fix disables these events for special files, closing potential side-channels for information exfiltration.

Risk Assessment

The organization may face information leakage about activity on special files, which could be exploited by malware to monitor other processes.

Recommendation

Immediately update the Linux kernel to a version containing the fix (commit in the fsnotify branch). A system reboot is required after the update.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: fsnotify: do not generate ACCESS/MODIFY events on child for special files inotify/fanotify do not allow users with no read access to a file to subscribe to events (e.g. IN_ACCESS/IN_MODIFY), but they do allow the same user to subscribe for watching events on children when the user has access to the parent directory (e.g. /dev). Users with no read access to a file but with read access to its parent directory can still stat the file and see if it was accessed/modified via atime/mtime change. The same is not true for special files (e.g. /dev/null). Users will not generally observe atime/mtime changes when other users read/write to special files, only when someone sets atime/mtime via utimensat(). Align fsnotify events with this stat behavior and do not generate ACCESS/MODIFY events to parent watchers on read/write of special files. The events are still generated to parent watchers on utimensat(). This closes some side-channels that could be possibly used for information exfiltration [1]. [1] https://snee.la/pdf/pubs/file-notification-attacks.pdf

Vulnerability data from NVD (NIST) · CISA KEV · EPSS