CVE-2026-89645

Resource leak via stale relocation-root references

Published Sep 11, 2026 · Updated Sep 11, 2026

Improper resource cleanup in Linux 5.7 allows attackers to retain btrfs relocation-root references during failed recovery. In btrfs_recover_relocation(), the out_unset path clears neither fs_root->reloc_root pointers nor their owned references after a later root load, insertion, or first transaction commit fails. Reachability requires privileged mounting of a pending-relocation btrfs image plus a recovery error; the demonstrated consequence is leaked references before the mount fails.

CVSS severityUnavailable
Unscored
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper resource cleanup in Linux 5.7 allows attackers to retain btrfs relocation-root references during failed recovery. In btrfs_recover_relocation(), the out_unset path clears neither fs_root->reloc_root pointers nor their owned references after a later root load, insertion, or first transaction commit fails. Reachability requires privileged mounting of a pending-relocation btrfs image plus a recovery error; the demonstrated consequence is leaked references before the mount fails.

The record

CVE
CVE-2026-89645
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.7
  2. Affected versionversion=f44deb7442edf42abee6be25fca7e3e86061b4c9 <2256d6dc5b88841a8a8b4fd9a9f04730705fb6fd
  3. Affected versionversion=f44deb7442edf42abee6be25fca7e3e86061b4c9 <4d43107e807bcd92621106b07f5011411c6341a8
  4. Affected versionversion=f44deb7442edf42abee6be25fca7e3e86061b4c9 <6d8ba4572922e336f0b59a80751b018e1e135164
  5. Affected versionversion=f44deb7442edf42abee6be25fca7e3e86061b4c9 <8a64baeb5bbb706b83d2235c1e39f5b77183817f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=5.7; version=f44deb7442edf42abee6be25fca7e3e86061b4c9 <2256d6dc5b88841a8a8b4fd9a9f04730705fb6fd; version=f44deb7442edf42abee6be25fca7e3e86061b4c9 <4d43107e807bcd92621106b07f5011411c6341a8; version=f44deb7442edf42abee6be25fca7e3e86061b4c9 <6d8ba4572922e336f0b59a80751b018e1e135164; version=f44deb7442edf42abee6be25fca7e3e86061b4c9 <8a64baeb5bbb706b83d2235c1e39f5b77183817f

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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