Known exploited vulnerability
CVE-2024-38475
The short answer
CVE-2024-38475 affects Apache Software Foundation Apache HTTP Server and is rated critical (CVSS 9.1). CISA added it to the Known Exploited Vulnerabilities catalog on 2025-05-01: attackers are using it, so patch it first. The vendor has linked a patch.
What it is
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.
Weakness: CWE-116.
Severity
9.1 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Exploited (CISA KEV)
Yes, since May 1, 2025
Federal due date May 22, 2025
EPSS, next 30 days
100%
Higher than 100% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- None
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected products
Apache HTTP Server, http_server, ontap_9. NVD's record lists the exact affected versions.
References
- httpd.apache.org/security/vulnerabilities_24.html Vendor Advisory
- security.netapp.com/advisory/ntap-20240712-0001/ Third Party Advisory
- github.com/apache/httpd/commit/9a6157d1e2f7ab15963020381054b48782bc18cf Patch
- httpd.apache.org/security/vulnerabilities_24.html Vendor Advisory
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0018 Third Party Advisory
- security.netapp.com/advisory/ntap-20240712-0001/ Third Party Advisory
- 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
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-38475 Third Party AdvisoryUS Government Resource
Questions
Is CVE-2024-38475 being exploited?
Yes. CISA added CVE-2024-38475 to its Known Exploited Vulnerabilities catalog on 2025-05-01, with a federal remediation due date of 2025-05-22.
How do I fix CVE-2024-38475?
CISA's 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.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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