CVE-2026-43066

Local denial of service via buffer-head leak

Published May 5, 2026 · Updated May 5, 2026

Memory resource leakage in ext4 fast-commit replay in Linux Kernel 5.10 through 7.0-rc5 allows local users to interrupt service. ext4_fc_replay_inode() obtains iloc.bh through ext4_get_fc_inode_loc() but four failure paths reach the common exit without calling brelse(), while also suppressing the underlying errors. Triggering requires local access and an ext4 fast-commit replay that reaches a metadata, buffer-sync, inode-marking, or inode-lookup failure path; the leak affects availability without reported data disclosure or modification.

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

Memory resource leakage in ext4 fast-commit replay in Linux Kernel 5.10 through 7.0-rc5 allows local users to interrupt service. ext4_fc_replay_inode() obtains iloc.bh through ext4_get_fc_inode_loc() but four failure paths reach the common exit without calling brelse(), while also suppressing the underlying errors. Triggering requires local access and an ext4 fast-commit replay that reaches a metadata, buffer-sync, inode-marking, or inode-lookup failure path; the leak affects availability without reported data disclosure or modification.

The record

CVE
CVE-2026-43066
Published
May 5, 2026
Updated
May 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-401, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 5, 2026CVE publishedPublication date reported by the CVE source.
  2. May 5, 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=5.10
  2. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <0892f12cd49fde5d5db68137923db107f894f3a3
  3. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <19782b4c793b49a6aa4abbb307ddff3610009d21
  4. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <5a63033696e60b5d70816f1d119645ac5b0b0a03
  5. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <9c90449a9ac2cd1ba540ad2561b8b70c1bfb0a25
  6. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <c426231e3d51916e83b6d1ab7ed8a65e83bca5b4
  7. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <ca99cbcc316cdfd2040cc2b13d1426ccb3b3b50b
  8. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <ec0a7500d8eace5b4f305fa0c594dd148f0e8d29
  9. Affected versionversion=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <f7817ad399d604e8639005d87d148b5ec626ad26

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.10; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <0892f12cd49fde5d5db68137923db107f894f3a3; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <19782b4c793b49a6aa4abbb307ddff3610009d21; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <5a63033696e60b5d70816f1d119645ac5b0b0a03; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <9c90449a9ac2cd1ba540ad2561b8b70c1bfb0a25; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <c426231e3d51916e83b6d1ab7ed8a65e83bca5b4; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <ca99cbcc316cdfd2040cc2b13d1426ccb3b3b50b; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <ec0a7500d8eace5b4f305fa0c594dd148f0e8d29; version=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 <f7817ad399d604e8639005d87d148b5ec626ad26

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499Endpoint Denial of Service

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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