CVE-2023-53317

Kernel warning via unchecked ext4 bitmap padding

Published Sep 16, 2025 · Updated Sep 16, 2025

Improper ext4 bitmap validation in the Linux kernel allows local users to trigger a kernel warning by mounting a crafted filesystem. ext4_validate_block_bitmap accepts set bits beyond the block-group boundary, so allocation scanning reaches an impossible extent and trips mb_find_extent. Exploitation requires local low-privileged access and a path that mounts an attacker-controlled ext4 filesystem.

CVSS severity5.5
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper ext4 bitmap validation in the Linux kernel allows local users to trigger a kernel warning by mounting a crafted filesystem. ext4_validate_block_bitmap accepts set bits beyond the block-group boundary, so allocation scanning reaches an impossible extent and trips mb_find_extent. Exploitation requires local low-privileged access and a path that mounts an attacker-controlled ext4 filesystem.

The record

CVE
CVE-2023-53317
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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 <1b90fbc7590124c57a2e590de7fd07eba26606f1
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5d356d902e9d5b1aaaaf2326d365340fa8a90c1b
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <775b00ba23f6f916fe2ac60c5ff7fd0fe4f28d0d
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d55e76e11592a1d18a179c7fd34ca1b52632beb3
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dba62fa84a8eac44a53a2862de8a40e5bdfa0ae3
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dd45e536f47a82e0a405f9a4b6c7ceb367171ee9
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e4d503c956a744cb59e509ca5f134cfad423c7a3
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fa08a7b61dff8a4df11ff1e84abfc214b487caf7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1b90fbc7590124c57a2e590de7fd07eba26606f1; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5d356d902e9d5b1aaaaf2326d365340fa8a90c1b; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <775b00ba23f6f916fe2ac60c5ff7fd0fe4f28d0d; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d55e76e11592a1d18a179c7fd34ca1b52632beb3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dba62fa84a8eac44a53a2862de8a40e5bdfa0ae3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dd45e536f47a82e0a405f9a4b6c7ceb367171ee9; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e4d503c956a744cb59e509ca5f134cfad423c7a3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fa08a7b61dff8a4df11ff1e84abfc214b487caf7

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5CISA ADPCVSS: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

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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