# cifs: fix loff_t underflow in cifs_remap_file_range() when len == 0

CVE record · `CVE-2026-89640`

- **Identifiers:** `CVE-2026-89640`
- **State:** Confirmed
- **Severity:** CVSS 7.1 High
- **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: `04b38d601239b4d9be641b412cf4b7456a041c67 to before 2c6eede83b3de1268db92c7e49741761c954aa26` (git)
  - affected: `04b38d601239b4d9be641b412cf4b7456a041c67 to before ce813e5eebf46851e872ce59bdc34dc5dd4e29a4` (git)
  - affected: `04b38d601239b4d9be641b412cf4b7456a041c67 to before f3d1ae1e6bc4a9f559185b6e7bd2b6375ec2fdd4` (git)
  - affected: `04b38d601239b4d9be641b412cf4b7456a041c67 to before 7f62817fe049b0f3652518c1ba72631ec1e0a322` (git)
  - affected: `04b38d601239b4d9be641b412cf4b7456a041c67 to before b098f5e5858797827666e6cd73033f52fc39b5f6` (git)
  - affected: `04b38d601239b4d9be641b412cf4b7456a041c67 to before c2a0dcb5a7a1516aa6eb6d5cedca6a8e76527028` (git)
  - affected: `04b38d601239b4d9be641b412cf4b7456a041c67 to before b057ca17b656345d04669cb87f2aff9b31d873db` (git)
  - affected: `04b38d601239b4d9be641b412cf4b7456a041c67 to before 6c322f5cf7476ded7a9a20f7be72462065a03c68` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `4.5`
  - unaffected: `before 4.5` (semver)
  - unaffected: `5.10.273 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.224 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.188 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.157 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.109 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.50 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

## 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

- 7.1 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0013, the 2nd 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-2026-89640](https://www.cve.org/CVERecord?id=CVE-2026-89640)
- [NVD: CVE-2026-89640](https://nvd.nist.gov/vuln/detail/CVE-2026-89640)

### References from the CNA

- <https://git.kernel.org/stable/c/2c6eede83b3de1268db92c7e49741761c954aa26>
- <https://git.kernel.org/stable/c/ce813e5eebf46851e872ce59bdc34dc5dd4e29a4>
- <https://git.kernel.org/stable/c/f3d1ae1e6bc4a9f559185b6e7bd2b6375ec2fdd4>
- <https://git.kernel.org/stable/c/7f62817fe049b0f3652518c1ba72631ec1e0a322>
- <https://git.kernel.org/stable/c/b098f5e5858797827666e6cd73033f52fc39b5f6>
- <https://git.kernel.org/stable/c/c2a0dcb5a7a1516aa6eb6d5cedca6a8e76527028>
- <https://git.kernel.org/stable/c/b057ca17b656345d04669cb87f2aff9b31d873db>
- <https://git.kernel.org/stable/c/6c322f5cf7476ded7a9a20f7be72462065a03c68>

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-2026-89640>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89640/>. Everything for agents: <https://agentprime.io/llms.txt>.