DEBIAN-CVE-2026-21876
The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 4.22.0 and 3.3.8, the current rule 922110 has a bug when processing multipart requests with multiple parts. When the first rule in a chain iterates over a collection (like `MULTIPART_PART_HEADERS`), the capture variables (`TX:0`, `TX:1`) get overwritten with each iteration. Only the last captured value is available to the chained rule, which means malicious charsets in earlier parts can be missed if a later part has a legitimate charset. Versions 4.22.0 and 3.3.8 patch the issue.
DEBIAN-CVE-2026-21876
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-21876
modsecurity-crs
Source reference: /affected/0/package/name
- Affected versions
- 3.3.4-1
Source reference:
/affected/0/versions - Fixed versions
- 3.3.4-1+deb12u1
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
modsecurity-crs
Source reference: /affected/1/package/name
- Affected versions
- 3.3.7-1
Source reference:
/affected/1/versions - Fixed versions
- 3.3.7-1+deb13u1
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
modsecurity-crs
Source reference: /affected/2/package/name
- Affected versions
- 3.3.7-1
Source reference:
/affected/2/versions - Fixed versions
- 3.3.8-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.3.4-1+deb12u1"
}
]
}
],
"package": {
"name": "modsecurity-crs",
"purl": "pkg:deb/debian/modsecurity-crs?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"3.3.4-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.3.7-1+deb13u1"
}
]
}
],
"package": {
"name": "modsecurity-crs",
"purl": "pkg:deb/debian/modsecurity-crs?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"3.3.7-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.3.8-1"
}
]
}
],
"package": {
"name": "modsecurity-crs",
"purl": "pkg:deb/debian/modsecurity-crs?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"3.3.7-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #57417 · Revision 1
- Added to Heist Feed
- Publisher date