# cifs: call pagecache_isize_extended() in cifs_setsize() when extending

CVE record · `CVE-2026-89642`

- **Identifiers:** `CVE-2026-89642`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 11 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 11 Sept 2026, 19:45 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 880e1b5883a5d78d916fa446791c48f28a16719b` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5463d96cd2e46064ceefcf861b028745a4f4c373` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 40c16040783abcc240bd1b453e679ea6ca30e19e` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before e1f692b6da3e632a25d0b3a99f833bb609bae1a3` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 12bafe32f09c0d24f5096154b59c347b9c6606e0` (git)
  - affected: `1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before c510edb9734af1c274d18f4f31a471a166bbc7e8` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.12`
  - unaffected: `before 2.6.12` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.114 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.57 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.4 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The cifs module in the Linux kernel, affected from 2.6.12 until fixed, can write stale dirty page data to the server when a file is extended, exposing old contents in the new range. The source gives few details on what an attacker needs. Upgrade to 6.1.191, 6.6.160, 6.12.114, or 6.18.57, or a later release in those series.

Written 12 Nov 2026.

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0017, the 6th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 11 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89642](https://www.cve.org/CVERecord?id=CVE-2026-89642)
- [NVD: CVE-2026-89642](https://nvd.nist.gov/vuln/detail/CVE-2026-89642)

### References from the CNA

- <https://git.kernel.org/stable/c/880e1b5883a5d78d916fa446791c48f28a16719b>
- <https://git.kernel.org/stable/c/5463d96cd2e46064ceefcf861b028745a4f4c373>
- <https://git.kernel.org/stable/c/40c16040783abcc240bd1b453e679ea6ca30e19e>
- <https://git.kernel.org/stable/c/e1f692b6da3e632a25d0b3a99f833bb609bae1a3>
- <https://git.kernel.org/stable/c/12bafe32f09c0d24f5096154b59c347b9c6606e0>
- <https://git.kernel.org/stable/c/c510edb9734af1c274d18f4f31a471a166bbc7e8>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-89642>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89642/>. Everything for agents: <https://agentprime.io/llms.txt>.