CVE-2024-38473Public exploitNetwork attack vector

Authentication bypass via uncanonicalized proxy request URLs

Published Jul 1, 2024 · Updated Feb 13, 2025

Improper output encoding in mod_proxy in Apache HTTP Server 2.4.0 through 2.4.59 allows remote attackers to bypass backend authentication. For requests proxied through SetHandler or other non-ProxyPass paths, proxy_handler builds a proxy filename but fails to invoke proxy_fixup to canonicalize and escape it. The server must load mod_proxy and use an alternate proxy mechanism, which can also appear in .htaccess, and successful requests expose resources protected only by backend authentication.

CVSS severity8.1
High
EPSS probability25.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper output encoding in mod_proxy in Apache HTTP Server 2.4.0 through 2.4.59 allows remote attackers to bypass backend authentication. For requests proxied through SetHandler or other non-ProxyPass paths, proxy_handler builds a proxy filename but fails to invoke proxy_fixup to canonicalize and escape it. The server must load mod_proxy and use an alternate proxy mechanism, which can also appear in .htaccess, and successful requests expose resources protected only by backend authentication.

The record

CVE
CVE-2024-38473
Published
Jul 1, 2024
Updated
Feb 13, 2025
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-116, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 2024CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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=2.4.0 <=2.4.59

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=2.4.0 <=2.4.59

Published CVSS scores

8.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
5.3Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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 exploitPublished

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output
T1190Exploit Public-Facing Application

Public exploit references

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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