CVE-2025-40179

Memory exhaustion via ext4 orphan replay

Published Nov 12, 2025 · Updated May 11, 2026

Resource exhaustion in Linux kernel 5.15 and later allows local users to consume excessive memory through ext4 orphan replay. Code in fs/ext4/orphan.c traverses an unbounded orphan file and pins all of its buffers while allocating block-descriptor storage. Reaching the flaw requires local creation or presentation of an absurdly large ext4 orphan file, and the resulting memory pressure can hang or crash the host.

CVSS severity7.0
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Linux kernel 5.15 and later allows local users to consume excessive memory through ext4 orphan replay. Code in fs/ext4/orphan.c traverses an unbounded orphan file and pins all of its buffers while allocating block-descriptor storage. Reaching the flaw requires local creation or presentation of an absurdly large ext4 orphan file, and the resulting memory pressure can hang or crash the host.

The record

CVE
CVE-2025-40179
Published
Nov 12, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 12, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <0a6ce20c156442a4ce2a404747bb0fb05d54eeb3
  2. Affected versionversion=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <2b9da798ff0f4d026c5f0f815047393ebe7d8859
  3. Affected versionversion=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <304fc34ff6fc8261138fd81f119e024ac3a129e9
  4. Affected versionversion=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <566a1d6084563bd07433025aa23bcea4427de107
  5. Affected versionversion=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <95a21611b14ae0a401720645245a8db16f040995
  6. Affected versionversion=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <a2d803fab8a6c6a874277cb80156dc114db91921
  7. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <0a6ce20c156442a4ce2a404747bb0fb05d54eeb3; version=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <2b9da798ff0f4d026c5f0f815047393ebe7d8859; version=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <304fc34ff6fc8261138fd81f119e024ac3a129e9; version=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <566a1d6084563bd07433025aa23bcea4427de107; version=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <95a21611b14ae0a401720645245a8db16f040995; version=02f310fcf47fa9311d6ba2946a8d19e7d7d11f37 <a2d803fab8a6c6a874277cb80156dc114db91921; version=5.15

Published CVSS scores

7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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

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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