CVE-2025-71237

System hang via FITRIM block-count underflow

Published Feb 18, 2026 · Updated Feb 18, 2026

Integer underflow in the Linux Kernel nilfs2 filesystem allows local users to hang the system through a crafted FITRIM request. The nilfs2 FITRIM path subtracts a too-small end_block into unsigned sector_t nblocks, turning the underflow into a huge discard request. Triggering the condition requires local access and the ability to issue FITRIM against nilfs2; prolonged bio processing holds ns_segctor_sem and blocks other tasks.

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

Integer underflow in the Linux Kernel nilfs2 filesystem allows local users to hang the system through a crafted FITRIM request. The nilfs2 FITRIM path subtracts a too-small end_block into unsigned sector_t nblocks, turning the underflow into a huge discard request. Triggering the condition requires local access and the ability to issue FITRIM against nilfs2; prolonged bio processing holds ns_segctor_sem and blocks other tasks.

The record

CVE
CVE-2025-71237
Published
Feb 18, 2026
Updated
Feb 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 18, 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 <4aa45f841413cca81882602b4042c53502f34cad
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b8c5ee234bd54f1447c846101fdaef2cf70c2149
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <df1e20796c9f3d541cca47fb72e4369ea135642d
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ea2278657ad0d62596589fbe2caf995e189e65e7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4aa45f841413cca81882602b4042c53502f34cad; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b8c5ee234bd54f1447c846101fdaef2cf70c2149; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <df1e20796c9f3d541cca47fb72e4369ea135642d; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ea2278657ad0d62596589fbe2caf995e189e65e7

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

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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