CVE-2025-71123

Kernel crash via unterminated ext4 mount options

Published Jan 14, 2026 · Updated Jan 14, 2026

Out-of-bounds read in ext4 mount-option parsing in Linux Kernel allows context-dependent attackers to crash the kernel via a crafted ext4 image. parse_apply_sb_mount_options() passes the 64-byte on-disk s_mount_opts array to strscpy_pad() as a string, causing strnlen() to read beyond it when no NUL byte is present. Exploitation requires the kernel to mount the crafted filesystem; the reported consequence is a fortify panic and service interruption.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in ext4 mount-option parsing in Linux Kernel allows context-dependent attackers to crash the kernel via a crafted ext4 image. parse_apply_sb_mount_options() passes the 64-byte on-disk s_mount_opts array to strscpy_pad() as a string, causing strnlen() to read beyond it when no NUL byte is present. Exploitation requires the kernel to mount the crafted filesystem; the reported consequence is a fortify panic and service interruption.

The record

CVE
CVE-2025-71123
Published
Jan 14, 2026
Updated
Jan 14, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 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=01829af7656b56d83682b3491265d583d502e502 <902ca2356f1e3ec5355c5808ad5d3f9d0095b0cc
  2. Affected versionversion=2a0cf438320cdb783e0378570744c0ef0d83e934 <db9ee13fab0267eccf6544ee35b16c9522db9aac
  3. Affected versionversion=6.18
  4. Affected versionversion=7bf46ff83a0ef11836e38ebd72cdc5107209342d
  5. Affected versionversion=8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 <5bbacbbf1ca4419861dca3c6b82707c10e9c021c
  6. Affected versionversion=8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 <ee5a977b4e771cc181f39d504426dbd31ed701cc
  7. Affected versionversion=a6e94557cd05adc82fae0400f6e17745563e5412
  8. Affected versionversion=b2bac84fde28fb6a88817b8b761abda17a1d300b
  9. Affected versionversion=e651294218d2684302ee5ed95ccf381646f3e5b4 <6e37143560e37869d51b7d9e0ac61fc48895f8a0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=01829af7656b56d83682b3491265d583d502e502 <902ca2356f1e3ec5355c5808ad5d3f9d0095b0cc; version=2a0cf438320cdb783e0378570744c0ef0d83e934 <db9ee13fab0267eccf6544ee35b16c9522db9aac; version=6.18; version=7bf46ff83a0ef11836e38ebd72cdc5107209342d; version=8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 <5bbacbbf1ca4419861dca3c6b82707c10e9c021c; version=8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 <ee5a977b4e771cc181f39d504426dbd31ed701cc; version=a6e94557cd05adc82fae0400f6e17745563e5412; version=b2bac84fde28fb6a88817b8b761abda17a1d300b; version=e651294218d2684302ee5ed95ccf381646f3e5b4 <6e37143560e37869d51b7d9e0ac61fc48895f8a0

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.1Canonical UbuntuCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.8Canonical UbuntuCVSS:3.1/AV:L/AC:L/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.

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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