Vulnerability in Apache HTTP Server
CVE-2024-38475
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.
EPSS: 1.000 (100.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Public proof-of-concept exploits
References
- security@apache.org (vendor-advisory, Vendor Advisory)
- security@apache.org (Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Patch)
- af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Third Party Advisory, US Government Resource)
Frequently asked questions
- What is CVE-2024-38475?
- CVE-2024-38475 is a critical-severity vulnerability in Apache HTTP Server, classified under Improper Encoding or Escaping of Output. CVSS score: 9.1/10. Published 2024-07-01.
- How severe is CVE-2024-38475?
- Critical severity. CVSS v3 base score is 9.1 out of 10.
- Is CVE-2024-38475 known to be exploited?
- Yes. CVE-2024-38475 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-05-01), indicating it is being actively exploited. 24 public proof-of-concept repositories are indexed.