CVE-2024-38475
Apache HTTP Server Improper Escaping of Output Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 22 May 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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.
- CVSS 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 99.96% probability · 100th percentile
- CISA KEV
- Listed 1 May 2025 · due 22 May 2025
- Weakness
- CWE-116
- Affected
- apache/http server · netapp/ontap 9 · sonicwall/sma 200 firmware · sonicwall/sma 210 firmware · sonicwall/sma 400 firmware · sonicwall/sma 410 firmware · sonicwall/sma 500v firmware
- Source
- security@apache.org
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. This vulnerability affects a common open-source component, third-party library, or a protocol used by different products. Please check with specific vendors for information on patching status. For more information, please see: https://httpd.apache.org/security/vulnerabilities_24.html ; https://nvd.nist.gov/vuln/detail/CVE-2024-38475
References
- https://httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisory
- https://security.netapp.com/advisory/ntap-20240712-0001/Third Party Advisory
- http://www.openwall.com/lists/oss-security/2024/07/01/8Third Party Advisory
- https://github.com/apache/httpd/commit/9a6157d1e2f7ab15963020381054b48782bc18cfPatch
- https://httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisory
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0018Third 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-40227Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-38475Third Party Advisory, US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.