Servers and applications
CVE-2011-4415
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…
- Severity
- Low 1.2
- Published
- 8 Nov 2011
- Last changed
- 16 Jun 2026
- Added to UpHeron
- 17 Oct 2026
- Exploit chance
- 3% in the next 30 daysHigher than 87% of CVEs. EPSS by FIRST, 12 Nov 2026
- Attack
- Needs local access · Only under certain conditions · No login needed
- Attacker can
- Slow it down
- CVSS vector
AV:L/AC:H/Au:N/C:N/I:N/A:P- Sources
- NVD
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 software
| Software | Affected versions |
|---|---|
Apache HTTP ServerServers and applications · cpe:a:apache:http_server |
All 55 release lines
|