CVE-2026-43338Public exploit

Local Btrfs transaction abort via qgroup ioctls

Published May 8, 2026 · Updated May 8, 2026

Improper transaction management in Linux Kernel allows local users to abort Btrfs transactions by issuing quota-group ioctls. The qgroup ioctl paths join a transaction without reserving space for quota-tree changes or their delayed references, forcing those updates into the global block reserve. Reachability requires a locally mounted Btrfs filesystem with quotas enabled and extensive qgroup churn near ENOSPC; the published reproducer is explicitly unlikely to model real use.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper transaction management in Linux Kernel allows local users to abort Btrfs transactions by issuing quota-group ioctls. The qgroup ioctl paths join a transaction without reserving space for quota-tree changes or their delayed references, forcing those updates into the global block reserve. Reachability requires a locally mounted Btrfs filesystem with quotas enabled and extensive qgroup churn near ENOSPC; the published reproducer is explicitly unlikely to model real use.

The record

CVE
CVE-2026-43338
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <386f5e16a383101a68e195c806b4eedb233cd1d3
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bb6eb33c908edbbb4d92abdc0c6c87f21b4952e8
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cf930a651eef6f8d915bf0ccd60c2045974f870c
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f9a4e3015db1aeafbef407650eb8555445ca943e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <386f5e16a383101a68e195c806b4eedb233cd1d3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bb6eb33c908edbbb4d92abdc0c6c87f21b4952e8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cf930a651eef6f8d915bf0ccd60c2045974f870c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f9a4e3015db1aeafbef407650eb8555445ca943e

Published CVSS scores

5.5NVDCVSS: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 exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

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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