CVE-2026-43117Network attack vector

Kernel crash via incorrect btrfs superblock lookup

Published May 6, 2026 · Updated May 6, 2026

A btrfs tracepoint flaw in the Linux Kernel allows remote attackers to crash the kernel by inducing file synchronization on an overlay mount. The btrfs_sync_file tracepoint reads dentry->d_sb, obtains the overlay superblock instead of the underlying btrfs superblock, and uses it for fsid assignment. Exploitation requires overlayfs layered over btrfs and a path that causes the tracepoint event to run; the reported consequence is a kernel crash.

CVSS severity9.1
Critical
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A btrfs tracepoint flaw in the Linux Kernel allows remote attackers to crash the kernel by inducing file synchronization on an overlay mount. The btrfs_sync_file tracepoint reads dentry->d_sb, obtains the overlay superblock instead of the underlying btrfs superblock, and uses it for fsid assignment. Exploitation requires overlayfs layered over btrfs and a path that causes the tracepoint event to run; the reported consequence is a kernel crash.

The record

CVE
CVE-2026-43117
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 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 <2e4adfaec97ee053ad1bdfb5036845e66f7e0d8a
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <32372781d664a9b03c40343e96c29d0a6139f97d
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a85b46db143fda5869e7d8df8f258ccef5fa1719
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c09a7446aab5773f38d6abb25fce99b8e1dfbc97
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d110d7cdb045715c0b45b0dfd974525bb38f653d

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2e4adfaec97ee053ad1bdfb5036845e66f7e0d8a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <32372781d664a9b03c40343e96c29d0a6139f97d; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a85b46db143fda5869e7d8df8f258ccef5fa1719; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c09a7446aab5773f38d6abb25fce99b8e1dfbc97; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d110d7cdb045715c0b45b0dfd974525bb38f653d

Published CVSS scores

9.1kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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