Local service hang via Btrfs transaction deadlock
Published Jun 20, 2024 · Updated May 11, 2026
Deadlock in Btrfs qgroup handling in Linux allows local users to hang filesystem operations through concurrent quota and balance operations. The quota-disable ioctl opens a transaction before waiting for the qgroup rescan worker, creating a circular wait when relocation or balance work joins and commits that transaction. Reaching the flaw requires local privileges to alter Btrfs quotas plus a concurrent rescan and transaction; the resulting availability loss is a persistent task and filesystem-operation hang.
Summary
What happened
Deadlock in Btrfs qgroup handling in Linux allows local users to hang filesystem operations through concurrent quota and balance operations. The quota-disable ioctl opens a transaction before waiting for the qgroup rescan worker, creating a circular wait when relocation or balance work joins and commits that transaction. Reaching the flaw requires local privileges to alter Btrfs quotas plus a concurrent rescan and transaction; the resulting availability loss is a persistent task and filesystem-operation hang.
The record
- CVE
- CVE-2022-48734
- Published
- Jun 20, 2024
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 20, 2024CVE publishedPublication date reported by the CVE source.
- May 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.
- Affected versionversion=4.4
- Affected versionversion=967ef5131e42d6e3bb216c44161d893048a49957 <26b3901d20bf9da2c6a00cb1fb48932166f80a45
- Affected versionversion=967ef5131e42d6e3bb216c44161d893048a49957 <31198e58c09e21d4f65c49d2361f76b87aca4c3f
- Affected versionversion=967ef5131e42d6e3bb216c44161d893048a49957 <32747e01436aac8ef93fe85b5b523b4f3b52f040
- Affected versionversion=967ef5131e42d6e3bb216c44161d893048a49957 <89d4cca583fc9594ee7d1a0bc986886d6fb587e6
- Affected versionversion=967ef5131e42d6e3bb216c44161d893048a49957 <e804861bd4e69cc5fe1053eedcb024982dde8e48
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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