# btrfs: drop recovered reloc root refs on recovery failure

CVE record · `CVE-2026-89645`

- **Identifiers:** `CVE-2026-89645`
- **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: `f44deb7442edf42abee6be25fca7e3e86061b4c9 to before f671ffc678e0247aad77126670cb28c766d6ab3d` (git)
  - affected: `f44deb7442edf42abee6be25fca7e3e86061b4c9 to before 7b8c6af17287899a5d00c70566831feac237d192` (git)
  - affected: `f44deb7442edf42abee6be25fca7e3e86061b4c9 to before 2256d6dc5b88841a8a8b4fd9a9f04730705fb6fd` (git)
  - affected: `f44deb7442edf42abee6be25fca7e3e86061b4c9 to before 8a64baeb5bbb706b83d2235c1e39f5b77183817f` (git)
  - affected: `f44deb7442edf42abee6be25fca7e3e86061b4c9 to before 4d43107e807bcd92621106b07f5011411c6341a8` (git)
  - affected: `f44deb7442edf42abee6be25fca7e3e86061b4c9 to before 6d8ba4572922e336f0b59a80751b018e1e135164` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.7`
  - unaffected: `before 5.7` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 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

## Machine-written summary

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

> The Linux kernel btrfs code is affected from 5.7 until fixed. When relocation recovery fails during mount, references to relocation roots can be left behind on filesystem roots. The source gives few details on attacker requirements. Upgrade to 6.1.191, 6.6.160, 6.12.109, 6.18.50, or a later fixed kernel.

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:** 0.0025, the 16th 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-2026-89645](https://www.cve.org/CVERecord?id=CVE-2026-89645)
- [NVD: CVE-2026-89645](https://nvd.nist.gov/vuln/detail/CVE-2026-89645)

### References from the CNA

- <https://git.kernel.org/stable/c/f671ffc678e0247aad77126670cb28c766d6ab3d>
- <https://git.kernel.org/stable/c/7b8c6af17287899a5d00c70566831feac237d192>
- <https://git.kernel.org/stable/c/2256d6dc5b88841a8a8b4fd9a9f04730705fb6fd>
- <https://git.kernel.org/stable/c/8a64baeb5bbb706b83d2235c1e39f5b77183817f>
- <https://git.kernel.org/stable/c/4d43107e807bcd92621106b07f5011411c6341a8>
- <https://git.kernel.org/stable/c/6d8ba4572922e336f0b59a80751b018e1e135164>

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-2026-89645>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89645/>. Everything for agents: <https://agentprime.io/llms.txt>.