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...
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.
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2011-4415- CVSS 2.0
- 1.2 Low
AV:L/AC:H/Au:N/C:N/I:N/A:P - Weakness
- CWE-20
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2011-4415- Updated
- 2026-11-02
EUVDEUVD-2011-4344 No score
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.
- Record
EUVD-2011-4344- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-43r8-mvrp-6q9c No score
The ap_pregsub function in server/util.c in the Apache HTTP Server 2.0.x through 2.0.64 and 2.2.x...
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.
- Record
GHSA-43r8-mvrp-6q9c- Weakness
- CWE-20
- Updated
- 2026-11-02
OSV No score
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.
- Record
CVE-2011-4415- Updated
- 2026-11-02
OSVDEBIAN-CVE-2011-4415 No score
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.
- Record
DEBIAN-CVE-2011-4415- Updated
- 2026-11-02
Affected products
Affected packages
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Exploit-DB | Apache < 2.0.64 / < 2.2.21 mod_setenvif - Integer Overflow | 2011-11-02 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, Exploit-DB, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2011-4415 is a low vulnerability (CVSS 1.2) in Apache Http Server, published November 8, 2011. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 3.02%, the 87th percentile. Fixed in apache2 2.4.1-1.
References
h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c03360041
halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/DemoExploit.html
gossamer-threads.com/lists/apache/dev/403775
nvd.nist.gov/vuln/detail/CVE-2011-4415
github.com/advisories/GHSA-43r8-mvrp-6q9c
security-tracker.debian.org/tracker/CVE-2011-4415