# CVE-2026-80961

## Summary

- **CVE ID:** CVE-2026-80961
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 13, 2026

## Description

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

dm-pcache: validate kset key_num and intra-segment bounds

Two more fields decoded from the cache device go unbounded. The kset
key_num drives cache_kset_crc() and the replay loop in cache_replay(),
the writeback worker and the GC worker, but only the magic and a
fixed-seed CRC are checked first, so a non-last kset whose key_num exceeds
the PCACHE_KSET_KEYS_MAX buffer reads past its end before the CRC compare.
A key's intra-segment offset and length in cache_key_decode() are taken
verbatim, so a key running past its segment is replayed into the cache
tree and the data CRC check and every later read hit then copy adjacent
persistent memory into the caller's bio -- an out-of-bounds read that
leaks to user space. Both fields are controlled by whoever supplies the
cache device (CAP_SYS_ADMIN); the CRC seed is public.

Add kset_onmedia_valid() to bound key_num before any kset read, and
reject a key whose offset plus length, computed in 64 bits, exceeds the
segment data_size. Valid metadata is unaffected.

## Affected Products

- Linux — Linux (1d57628ff95b32d5cfa8d8f50e07690c161e9cf0)
- Linux — Linux (6.18)
- Linux — Linux (0)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/d8caf96040a06096276ab72f5e1e8547c014c564)
- [CNA](https://git.kernel.org/stable/c/5ac38f4b4862fad6e7270fde5c3356a822ce74ca)
- [CNA](https://git.kernel.org/stable/c/f11deb032fd84081e7831cffcba895d893054a22)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.16%
- **EPSS Percentile:** 5.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-20._