DEBIAN-CVE-2026-21876

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Source
https://security-tracker.debian.org/tracker/CVE-2026-21876
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-21876
Upstream
Published
2026-01-08T14:15:57.087Z
Modified
2026-01-09T11:07:15.926777Z
Severity
  • 9.3 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N CVSS Calculator
Summary
[none]
Details

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.

References

Affected packages

Debian:11 / modsecurity-crs

Package

Name
modsecurity-crs
Purl
pkg:deb/debian/modsecurity-crs?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

3.*

3.3.0-1
3.3.0-1+deb11u1
3.3.2-1
3.3.4-1~deb11u1
3.3.4-1
3.3.5-1
3.3.5-2
3.3.6-1
3.3.7-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json"

Debian:12 / modsecurity-crs

Package

Name
modsecurity-crs
Purl
pkg:deb/debian/modsecurity-crs?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

3.*

3.3.4-1
3.3.5-1
3.3.5-2
3.3.6-1
3.3.7-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json"

Debian:13 / modsecurity-crs

Package

Name
modsecurity-crs
Purl
pkg:deb/debian/modsecurity-crs?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

3.*

3.3.7-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json"

Debian:14 / modsecurity-crs

Package

Name
modsecurity-crs
Purl
pkg:deb/debian/modsecurity-crs?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

3.*

3.3.7-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-21876.json"