CVE-2021-46945

Configured panic bypass via premature read-only return

Published Feb 27, 2024 · Updated May 11, 2026

Improper error handling in Linux kernel 5.11 before 5.11.20 and 5.12 before 5.12.3 allows local users to bypass an ext4 panic. ext4_handle_error() returns on sb_rdonly() or continue_fs before evaluating ERRORS_PANIC, skipping the configured panic path. Reaching the behavior requires control of ext4 mount operations and an errors=panic filesystem; the forced error leaves the host running.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper error handling in Linux kernel 5.11 before 5.11.20 and 5.12 before 5.12.3 allows local users to bypass an ext4 panic. ext4_handle_error() returns on sb_rdonly() or continue_fs before evaluating ERRORS_PANIC, skipping the configured panic path. Reaching the behavior requires control of ext4 mount operations and an errors=panic filesystem; the forced error leaves the host running.

The record

CVE
CVE-2021-46945
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=014c9caa29d3a44e0de695c99ef18bec3e887d52 <1e9ea8f4637026b8e965128953f2da061ccae9c4
  2. Affected versionversion=014c9caa29d3a44e0de695c99ef18bec3e887d52 <64e1eebe2131183174f4fbb6b1491355f96c6cde
  3. Affected versionversion=014c9caa29d3a44e0de695c99ef18bec3e887d52 <ac2f7ca51b0929461ea49918f27c11b680f28995
  4. Affected versionversion=5.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=014c9caa29d3a44e0de695c99ef18bec3e887d52 <1e9ea8f4637026b8e965128953f2da061ccae9c4; version=014c9caa29d3a44e0de695c99ef18bec3e887d52 <64e1eebe2131183174f4fbb6b1491355f96c6cde; version=014c9caa29d3a44e0de695c99ef18bec3e887d52 <ac2f7ca51b0929461ea49918f27c11b680f28995; version=5.11

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.4SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

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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