CVE-2026-74572

System hang via metadata writeback lock deadlock

Published Aug 15, 2026 · Updated Aug 15, 2026

Deadlock in zoned Btrfs in Linux allows local users to hang the system during concurrent metadata writeback and transaction commit. In btree_writepages(), the tree-log branch retains zoned_meta_io_lock while btrfs_zone_finish_one_bg() waits for a transaction whose committer needs that lock. The path requires a zoned Btrfs filesystem, failed tree-log block-group activation, and overlapping writeback and commit activity; reaching it stalls both tasks and hangs the system.

CVSS severity7.5
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in zoned Btrfs in Linux allows local users to hang the system during concurrent metadata writeback and transaction commit. In btree_writepages(), the tree-log branch retains zoned_meta_io_lock while btrfs_zone_finish_one_bg() waits for a transaction whose committer needs that lock. The path requires a zoned Btrfs filesystem, failed tree-log block-group activation, and overlapping writeback and commit activity; reaching it stalls both tasks and hangs the system.

The record

CVE
CVE-2026-74572
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-833, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <18577e77c2c8adaadf1f7c6e9bcd1c0b14e5dcdd
  2. Affected versionversion=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <1ebe51c29fa9755d5b2fea28727c051117907cf8
  3. Affected versionversion=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <75859a7cd77cd2ddaddbcb963e3fcd34738953af
  4. Affected versionversion=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <c3320873e0c04ce7b746fc8fe948f07bbbbdec33
  5. Affected versionversion=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <deddd28fd83c264ee2ff5cd6b34449a9f1be6112
  6. Affected versionversion=6.5.5 <6.6
  7. Affected versionversion=6.6
  8. Affected versionversion=fca3a1cd3ba47f1815e0c0fcdc9aafaf02ee0a75

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <18577e77c2c8adaadf1f7c6e9bcd1c0b14e5dcdd; version=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <1ebe51c29fa9755d5b2fea28727c051117907cf8; version=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <75859a7cd77cd2ddaddbcb963e3fcd34738953af; version=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <c3320873e0c04ce7b746fc8fe948f07bbbbdec33; version=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <deddd28fd83c264ee2ff5cd6b34449a9f1be6112; version=6.5.5 <6.6; version=6.6; version=fca3a1cd3ba47f1815e0c0fcdc9aafaf02ee0a75

Published CVSS scores

7.5CVE ProgramCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-833Deadlock
T1499Endpoint Denial of Service

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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