CVE-2023-53503

Host crash via ext4 block-group underflow

Published Oct 1, 2025 · Updated Oct 1, 2025

Denial of service in affected Linux kernel branches allows local users with block-device write access to crash the host. A corrupted mounted ext4 superblock can make block-group calculation underflow, after which ext4_get_group_info() treats the resulting invalid group number as a fatal BUG_ON condition. Exploitation requires root-equivalent block-device access, and the documented consequence is a host crash rather than data disclosure or privilege escalation.

CVSS severity5.5
Medium
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

Denial of service in affected Linux kernel branches allows local users with block-device write access to crash the host. A corrupted mounted ext4 superblock can make block-group calculation underflow, after which ext4_get_group_info() treats the resulting invalid group number as a fatal BUG_ON condition. Exploitation requires root-equivalent block-device access, and the documented consequence is a host crash rather than data disclosure or privilege escalation.

The record

CVE
CVE-2023-53503
Published
Oct 1, 2025
Updated
Oct 1, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Oct 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 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 <100c0ad6c04597fefeaaba2bb1827cc015d95067
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <31668cebf45adfb6283e465e641c4f5a21b07afa
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5354b2af34064a4579be8bc0e2f15a7b70f14b5f
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <620a3c28221bb219b81bc0bffd065cc187494302
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b4319e457d6e3fb33e443efeaf4634fc36e8a9ed

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <100c0ad6c04597fefeaaba2bb1827cc015d95067; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <31668cebf45adfb6283e465e641c4f5a21b07afa; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5354b2af34064a4579be8bc0e2f15a7b70f14b5f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <620a3c28221bb219b81bc0bffd065cc187494302; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b4319e457d6e3fb33e443efeaf4634fc36e8a9ed

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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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