CVE-2023-53569

Undefined behavior via unchecked ext2 block-size shift

Published Oct 4, 2025 · Updated Oct 4, 2025

Improper input validation in the Linux kernel ext2 mount path allows local users to trigger undefined behavior with a crafted image. The ext2_fill_super function uses the on-disk s_log_block_size value as a left-shift count without first enforcing its maximum valid value. The flaw is reached when an affected kernel mounts the image, and public sources identify no specific crash, corruption, or disclosure outcome.

CVSS severity7.8
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in the Linux kernel ext2 mount path allows local users to trigger undefined behavior with a crafted image. The ext2_fill_super function uses the on-disk s_log_block_size value as a left-shift count without first enforcing its maximum valid value. The flaw is reached when an affected kernel mounts the image, and public sources identify no specific crash, corruption, or disclosure outcome.

The record

CVE
CVE-2023-53569
Published
Oct 4, 2025
Updated
Oct 4, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 4, 2025Record 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 <0ebfaf14150f55550cffb1148ed3920143c7a69c
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <22ab5fed07ad4b206ea910fd0132d1a0d4831584
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <451b98155be5dfee05bc6e7c8b30c0be4add3f71
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <62aeb94433fcec80241754b70d0d1836d5926b0a
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <99f8a15af6c9f0653193104a9e70891f950c6001
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c2e7776843a953fd7e48895c3880c277f996193e
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c4813f858e5c3e4c4659ce95385c1c400c593e1e
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e6f4fb28890c1361e0db9eb1adee3fc04e7fe7f5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0ebfaf14150f55550cffb1148ed3920143c7a69c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <22ab5fed07ad4b206ea910fd0132d1a0d4831584; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <451b98155be5dfee05bc6e7c8b30c0be4add3f71; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <62aeb94433fcec80241754b70d0d1836d5926b0a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <99f8a15af6c9f0653193104a9e70891f950c6001; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c2e7776843a953fd7e48895c3880c277f996193e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c4813f858e5c3e4c4659ce95385c1c400c593e1e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e6f4fb28890c1361e0db9eb1adee3fc04e7fe7f5

Published CVSS scores

7.8NIST NVDCVSS: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

No sourced classifications are available.

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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