CVE Catalog

CVE-2026-31694

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

3th percentile - higher than 3% of all known CVEs

Summary

In the Linux kernel FUSE filesystem, a vulnerability exists due to missing validation of directory entry (dirent) size before copying into the page cache. A malicious FUSE server can send a dirent exceeding PAGE_SIZE, causing a buffer overflow during memcpy() that overwrites adjacent kernel pages.

Risk Assessment

An attacker controlling a FUSE server can exploit this to corrupt kernel memory, potentially leading to privilege escalation or system crash (DoS).

Recommendation

Immediately update the Linux kernel to a version containing the fix that rejects dirents that cannot fit in a single page before inserting them into the readdir cache.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: fuse: reject oversized dirents in page cache fuse_add_dirent_to_cache() computes a serialized dirent size from the server-controlled namelen field and copies the dirent into a single page-cache page. The existing logic only checks whether the dirent fits in the remaining space of the current page and advances to a fresh page if not. It never checks whether the dirent itself exceeds PAGE_SIZE. As a result, a malicious FUSE server can return a dirent with namelen=4095, producing a serialized record size of 4120 bytes. On 4 KiB page systems this causes memcpy() to overflow the cache page by 24 bytes into the following kernel page. Reject dirents that cannot fit in a single page before copying them into the readdir cache.

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