CVE-2026-43393

Local denial of service via chunk-map leak

Published May 8, 2026 · Updated May 8, 2026

Memory leakage in the Linux Kernel Btrfs subsystem from 6.12 allows local users to interrupt service through repeated block-map errors. The btrfs_map_block() error path returns -EINVAL after btrfs_chunk_map_num_copies() without releasing the chunk map it just acquired. Low-privileged local access and a reachable Btrfs mapping error are required; repeated calls retain kernel memory until service is interrupted.

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 leakage in the Linux Kernel Btrfs subsystem from 6.12 allows local users to interrupt service through repeated block-map errors. The btrfs_map_block() error path returns -EINVAL after btrfs_chunk_map_num_copies() without releasing the chunk map it just acquired. Low-privileged local access and a reachable Btrfs mapping error are required; repeated calls retain kernel memory until service is interrupted.

The record

CVE
CVE-2026-43393
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-401, T1499.001
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=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <0e4aaf5a3212b6a469c2489637c29a8e2a5062a5
  2. Affected versionversion=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <4f90c5c2698383984102401b1724b0b67da832ab
  3. Affected versionversion=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <7bdf00ed75c477252578068dba19934cd825f20a
  4. Affected versionversion=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <f15fb3d41543244d1179f423da4a4832a55bc050
  5. Affected versionversion=6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <0e4aaf5a3212b6a469c2489637c29a8e2a5062a5; version=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <4f90c5c2698383984102401b1724b0b67da832ab; version=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <7bdf00ed75c477252578068dba19934cd825f20a; version=0ae653fbec2b9fbc72c65a0c99528990bfb2136d <f15fb3d41543244d1179f423da4a4832a55bc050; version=6.12

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 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
T1499.001OS Exhaustion Flood

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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