CVE-2026-43358

Local service interruption via unbalanced RCU unlock

Published May 8, 2026 · Updated May 8, 2026

RCU locking error in the Btrfs subsystem of Linux Kernel allows local users to interrupt service during extent-buffer release. The error path in try_release_subpage_extent_buffer exits its loop without taking rcu_read_lock, but execution still reaches the unconditional rcu_read_unlock after the loop. Reaching the flaw requires local low-privileged access and use of the affected Btrfs path; the public record does not specify whether interruption manifests as a hang, crash, or reboot.

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

RCU locking error in the Btrfs subsystem of Linux Kernel allows local users to interrupt service during extent-buffer release. The error path in try_release_subpage_extent_buffer exits its loop without taking rcu_read_lock, but execution still reaches the unconditional rcu_read_unlock after the loop. Reaching the flaw requires local low-privileged access and use of the affected Btrfs path; the public record does not specify whether interruption manifests as a hang, crash, or reboot.

The record

CVE
CVE-2026-43358
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=10ec363cfefeeb77fda4c1ac20a531f21de45264
  2. Affected versionversion=6.17
  3. Affected versionversion=ad580dfa388fabb52af033e3f8cc5d04be985e54 <35b0c8768e848e1b7e32052db36b5fa59b6a33a1
  4. Affected versionversion=ad580dfa388fabb52af033e3f8cc5d04be985e54 <5e1ab71f74a1e61f1254dff128a764fdebaec0b8
  5. Affected versionversion=ad580dfa388fabb52af033e3f8cc5d04be985e54 <b2840e33127ce0eea880504b7f133e780f567a9b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=10ec363cfefeeb77fda4c1ac20a531f21de45264; version=6.17; version=ad580dfa388fabb52af033e3f8cc5d04be985e54 <35b0c8768e848e1b7e32052db36b5fa59b6a33a1; version=ad580dfa388fabb52af033e3f8cc5d04be985e54 <5e1ab71f74a1e61f1254dff128a764fdebaec0b8; version=ad580dfa388fabb52af033e3f8cc5d04be985e54 <b2840e33127ce0eea880504b7f133e780f567a9b

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
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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