Description

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.

INFO

Published Date :

2026-01-08T13:55:37.102Z

Last Modified :

2026-04-09T15:41:17.073Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2026-21876 vulnerability.

Vendors Products
Owasp
  • Coreruleset
  • Owasp Modsecurity Core Rule Set

CVSS Vulnerability Scoring System

Detailed values of each vector for above chart.
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact