CVE-2026-93201 is a vulnerability in Linux Kernel
Published on September 17, 2026
dm-pcache: validate seg_id fields from persistent memory
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.
Products Associated with CVE-2026-93201
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Affected Versions
Linux:- Version 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 and below b4bf8af5e7d7db4c5e179e15017da55857761ac4 is affected.
- Version 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 and below 90c990a68460d7b5720e5634cf650eccdf0f4098 is affected.
- Version 6.18 is affected.
- Before 6.18 is unaffected.
- Version 7.2.6, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.