What’s Vulnerable › Vulnerabilities

CVE-2011-4415

• Severity: low (CVSS 1.2 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2011-11-08 · updated 2026-06-16
• Weakness: CWE-20

Description

The ap_pregsub function in server/util.c in the Apache HTTP Server 2.0.x through 2.0.64 and 2.2.x through 2.2.21, when the mod_setenvif module is enabled, does not restrict the size of values of environment variables, which allows local users to cause a denial of service (memory consumption or NULL pointer dereference) via a .htaccess file with a crafted SetEnvIf directive, in conjunction with a crafted HTTP request header, related to (1) the "len +=" statement and (2) the apr_pcalloc function call, a different vulnerability than CVE-2011-3607.

Affected products

• Apache HTTP Server: 2.0, 2.0.9, 2.0.28, 2.0.28-beta, 2.0.32, 2.0.32-beta (+49)

References

• http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c03360041
• http://www.gossamer-threads.com/lists/apache/dev/403775
• http://www.halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/
• http://www.halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/DemoExploit.html
• http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c03360041
• http://www.gossamer-threads.com/lists/apache/dev/403775
• http://www.halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/
• http://www.halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/DemoExploit.html

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