apache2 — security advisory
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.
- Products
- apache2
- Affected versions
- Not specified
- Fixed versions
- 2.4.1-1
- CVEs
- CVE-2011-4415
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:29 UTC · Revision 1
Source evidence
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.
osv:DEBIAN-CVE-2011-4415
apache2
Fixed versions: 2.4.1-1
apache2
Fixed versions: 2.4.1-1
apache2
Fixed versions: 2.4.1-1
Complete source record
{
"id": "abe8df2e154313e044c68da0d77c07b061d0e93639c372f2929a3cebee14459a",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2011-4415",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2011-4415",
"summary": "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.",
"evidence": "osv:DEBIAN-CVE-2011-4415",
"products": [
{
"name": {
"value": "apache2",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.4.1-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "apache2",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.4.1-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "apache2",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.4.1-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "unknown",
"structured": {
"id": "DEBIAN-CVE-2011-4415",
"aliases": [
"DEBIAN-CVE-2011-4415"
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.4.1-1"
}
]
}
],
"package": {
"name": "apache2",
"purl": "pkg:deb/debian/apache2?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2011-4415.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.4.1-1"
}
]
}
],
"package": {
"name": "apache2",
"purl": "pkg:deb/debian/apache2?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2011-4415.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.4.1-1"
}
]
}
],
"package": {
"name": "apache2",
"purl": "pkg:deb/debian/apache2?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2011-4415.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
}
],
"modified": "2026-10-23T17:47:22.486566716Z",
"provider": "osv",
"upstream": [
"CVE-2011-4415"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2011-4415"
]
},
"related_cves": [
{
"value": "CVE-2011-4415",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 416588,
"published_at": "2011-11-08T11:55:05.85+00:00"
}