CVE-2024-38475: Apache HTTP Server Improper Escaping of Output Vulnerability

CISA Known Exploited Vulnerabilities

Name

Apache HTTP Server Improper Escaping of Output Vulnerability

Vendor

Apache

Product

HTTP Server

Added to the catalog

2025-05-01

Due date for US federal agencies

2025-05-22

Weaknesses

CWE-116

Catalog version

2026.10.30

Apache HTTP Server contains an improper escaping of output vulnerability in mod_rewrite that allows an attacker to map URLs to filesystem locations that are permitted to be served by the server but are not intentionally/directly reachable by any URL, resulting in code execution or source code disclosure.

Required action (CISA)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://httpd.apache.org/security/vulnerabilities_24.html
• https://nvd.nist.gov/vuln/detail/CVE-2024-38475

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2024-07-01T19:15:04.883

Last modified

2026-06-17T07:40:21.380

Weaknesses

CWE-116

Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to map URLs to filesystem locations that are permitted to be served by the server but are not intentionally/directly reachable by any URL, resulting in code execution or source code disclosure.

Substitutions in server context that use a backreferences or variables as the first segment of the substitution are affected.  Some unsafe RewiteRules will be broken by this change and the rewrite flag "UnsafePrefixStat" can be used to opt back in once ensuring the substitution is appropriately constrained.

References

• https://httpd.apache.org/security/vulnerabilities_24.html (Vendor Advisory)
• https://security.netapp.com/advisory/ntap-20240712-0001/ (Third Party Advisory)
• http://www.openwall.com/lists/oss-security/2024/07/01/8 (Third Party Advisory)
• https://github.com/apache/httpd/commit/9a6157d1e2f7ab15963020381054b48782bc18cf (Patch)
• https://httpd.apache.org/security/vulnerabilities_24.html (Vendor Advisory)
• https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0018 (Third Party Advisory)
• https://security.netapp.com/advisory/ntap-20240712-0001/ (Third Party Advisory)
• https://www.blackhat.com/us-24/briefings/schedule/index.html#confusion-attacks-exploiting-hidden-semantic-ambiguity-in-apache-http-server-pre-recorded-40227 (Third Party Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-38475 (Third Party Advisory, US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:15.686Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2024-38475

CVE record

Title (CNA)

Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path.

Assigner

apache

State

PUBLISHED

Published

2024-07-01T18:15:12.292Z

Updated

2025-11-03T21:55:40.951Z

Problem types

CWE-116 Improper Encoding or Escaping of Output

Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to map URLs to filesystem locations that are permitted to be served by the server but are not intentionally/directly reachable by any URL, resulting in code execution or source code disclosure.

Substitutions in server context that use a backreferences or variables as the first segment of the substitution are affected.  Some unsafe RewiteRules will be broken by this change and the rewrite flag "UnsafePrefixStat" can be used to opt back in once ensuring the substitution is appropriately constrained.

References

• https://httpd.apache.org/security/vulnerabilities_24.html
• https://security.netapp.com/advisory/ntap-20240712-0001/

Read on 2026-11-03T02:06:49.554Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2024/38xxx/CVE-2024-38475.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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