CVE-2026-80956

In the Linux kernel, the following vulnerability has been resolved:

dm-pcache: only hand out initialized cache segments

get_cache_segment() scans the segment map up to cache->n_segs, the

physical device segment count, but cache_segs_init() only initializes

the first cache_info->n_segs segments. A crafted image with

cache_info->n_segs smaller than the device count leaves the remaining

pcache_cache_segment structs zeroed (segment.data == NULL), and the

allocator can hand one to cache_kset_close(), which writes through the

returned segment's data pointer with no NULL check.

Bound the allocator's search to cache_info->n_segs so only initialized

segments are ever returned. A conforming cache sets n_segs equal to the

device segment count, so this rejects nothing legitimate.