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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-21876 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/coreruleset/coreruleset/commit/80d80473abf71bd49bf6d3c1ab221e3c74e4eb83 GitHub, Inc.
https://github.com/coreruleset/coreruleset/commit/9917985de09a6cf38b3261faf9105e909d67a7d6 GitHub, Inc.
https://github.com/coreruleset/coreruleset/releases/tag/v3.3.8 GitHub, Inc.
https://github.com/coreruleset/coreruleset/releases/tag/v4.22.0 GitHub, Inc.
https://github.com/coreruleset/coreruleset/security/advisories/GHSA-36fv-25j3-r2c5 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-794 Incomplete Filtering of Multiple Instances of Special Elements GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-21876
NVD Published Date:
01/08/2026
NVD Last Modified:
01/08/2026
Source:
GitHub, Inc.