CVE-2011-4415: Apache HTTP Server

Low severity, CVSS 1.2. EPSS: 3% chance of exploitation in the next 30 days.

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: version 2.0 only; version 2.0.9 only; version 2.0.28 only; version 2.0.32 only; version 2.0.34 only; version 2.0.35 only; …

Published 2011-11-08. Last modified 2026-06-16.