CVE-2026-43299

Kernel crash via read-only Btrfs repair assertion

Published May 8, 2026 · Updated May 8, 2026

Denial of service in Linux Kernel 3.13 through 6.19.5 allows local users to crash the system during concurrent Btrfs error recovery. When ENOSPC aborts a transaction and flips the filesystem read-only during a pending read repair, btrfs_repair_io_failure() asserts that SB_RDONLY is clear and triggers a kernel BUG instead of returning. Exploitation requires a mounted Btrfs filesystem, a critical ENOSPC transition, and overlapping read repair; the bounded consequence is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux Kernel 3.13 through 6.19.5 allows local users to crash the system during concurrent Btrfs error recovery. When ENOSPC aborts a transaction and flips the filesystem read-only during a pending read repair, btrfs_repair_io_failure() asserts that SB_RDONLY is clear and triggers a kernel BUG instead of returning. Exploitation requires a mounted Btrfs filesystem, a critical ENOSPC transition, and overlapping read repair; the bounded consequence is a kernel crash.

The record

CVE
CVE-2026-43299
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
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 <8ceaad6cd6e7fa5f73b0b2796a2e85d75d37e9f3
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f6df18c001e3dcebc08482d0adeacd0cfea08593

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8ceaad6cd6e7fa5f73b0b2796a2e85d75d37e9f3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f6df18c001e3dcebc08482d0adeacd0cfea08593

Published CVSS scores

5.5NIST NVDCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1499.004Endpoint Denial of Service: Application or System Exploitation

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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