CVE Catalog

CVE-2026-93201

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, the dm-pcache module did not validate cache segment IDs from persistent memory before indexing into cache->segments[]. With only CRC protection using a public seed, an attacker with CAP_SYS_ADMIN supplying the cache device could cause out-of-bounds reads and writes via crafted metadata. The fix adds validation and rejects invalid segment IDs with -EIO.

Risk Assessment

A local attacker with privileges to load device tables could trigger out-of-bounds memory access, potentially leading to privilege escalation or system compromise.

Recommendation

Upgrade the Linux kernel to a version containing the validation fix and restrict device table load permissions.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: dm-pcache: validate seg_id fields from persistent memory cache_pos_decode(), cache_key_decode() and the last-kset branches of cache_replay(), the writeback worker and the GC worker take a cache segment id from the cache device metadata and index cache->segments[] with it without checking it against cache->n_segs. That metadata is only CRC-protected with a fixed public seed, so whoever supplies the cache device on a table load (CAP_SYS_ADMIN) controls the id; an out-of-range value forms a wild pcache_cache_segment pointer that is dereferenced and written through -- an out-of-bounds read and write driven by on-disk data. Add cache_seg_id_valid() and reject an out-of-range id at each decode site, failing the operation with -EIO instead of indexing past the array. Bound the id against the initialized-segment count (cache_info.n_segs) rather than the physical device total. A forged cache_info.n_segs below seg_num otherwise leaves segments[cache_info.n_segs..seg_num) as zeroed structs whose data pointer is NULL, so a forged id in that window would still be dereferenced. A later patch guarantees cache_info.n_segs <= seg_num, and a driver-created cache sets the two equal, so valid images are unaffected.

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