Known exploited vulnerability · CISA KEV

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

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.

CVE-2024-38475

Exploited in the wild. Fix this first.

CISA added it to the Known Exploited Vulnerabilities catalog on 2025-05-01: attackers are using it right now.

CISA KEV: Listed; Added 2025-05-01 · federal fix-by 2025-05-22
EPSS (30 days): over 99.9%; Higher than 99.9% of CVEs · 2026-11-01
CVSS v3.1: 9.1 Critical; CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

What CISA says

Apache HTTP Server Improper Escaping of Output Vulnerability

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

NVD description · published 2024-07-01

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.

Full record on NVD

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How to check if you are exposed to CVE-2024-38475

Find every Apache HTTP Server system you or your clients run, including ones exposed to the internet. Those come first: CISA only lists flaws attackers are already using.
Compare each version with the fixed versions in the vendor advisory below. Where no fix exists yet, apply the vendor’s mitigation or take the system off the internet.
Run a credentialed vulnerability scan to catch the systems you missed, then check that the next scan no longer reports CVE-2024-38475.

US federal agencies had to fix this by 2025-05-22. Everyone else should treat that deadline as a guide: if it has passed, this is overdue.

Affected versions

Versions the National Vulnerability Database lists as vulnerable to CVE-2024-38475. Check the vendor advisory for the exact fixed builds before you sign anything off.

Product	Vulnerable versions
Apache Http Server	from 2.4.0 before 2.4.60
Netapp Ontap 9	all versions
Sonicwall SMA 200 Firmware	before 10.2.1.14-75sv
Sonicwall SMA 210 Firmware	before 10.2.1.14-75sv
Sonicwall SMA 400 Firmware	before 10.2.1.14-75sv
Sonicwall SMA 410 Firmware	before 10.2.1.14-75sv

NVD lists 1 more affected product; see the full record on NVD.

Timeline

2024-07-01 · Published in the National Vulnerability Database
2025-05-01 · Added to CISA's Known Exploited Vulnerabilities catalog, 304 days after it was published
2025-05-22 · Fix-by date for US federal agencies, passed 528 days ago

Vendor advisories and fixes

https://httpd.apache.org/security/vulnerabilities_24.html

Weakness type

CWE-116

More exploited Apache vulnerabilities

CISA lists 41 exploited Apache vulnerabilities. The closest matches:

Keep going

Sources: CISA Known Exploited Vulnerabilities catalog (version 2026.10.30); EPSS data from FIRST.org; CVSS and descriptions from the NIST National Vulnerability Database. Checked 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.