CVE-2022-23943Network attack vector

Remote heap overwrite via mod_sed bounds error

Published Mar 14, 2022 · Updated Aug 3, 2024

Out-of-bounds write in mod_sed in Apache HTTP Server 2.4.52 and earlier allows remote attackers to overwrite heap memory via crafted HTTP content. The filter used signed integer buffer sizes and arithmetic, so large or wrapped lengths could miscompute allocation and write past the heap buffer. Exploitation requires mod_sed to be enabled; the resulting overwrite can corrupt process memory and cause crashes or potentially broader compromise.

CVSS severity9.8
Critical
EPSS probability50.40%
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 write in mod_sed in Apache HTTP Server 2.4.52 and earlier allows remote attackers to overwrite heap memory via crafted HTTP content. The filter used signed integer buffer sizes and arithmetic, so large or wrapped lengths could miscompute allocation and write past the heap buffer. Exploitation requires mod_sed to be enabled; the resulting overwrite can corrupt process memory and cause crashes or potentially broader compromise.

The record

CVE
CVE-2022-23943
Published
Mar 14, 2022
Updated
Aug 3, 2024
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-787, CWE-190, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=2.4 <=2.4.52

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=2.4 <=2.4.52

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-190Integer Overflow or Wraparound
T1190Exploit Public-Facing Application

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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