CVEvulnerability

CVE-2026-21876

5.3 MEDIUM Published 2026-01-08 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2026-01-08
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
9.3 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
CVSS 3.1 ([email protected])
5.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weaknesses
CWE-794

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.

Affected configurations

• owasp owasp modsecurity core rule set (< 3.3.8) • owasp owasp modsecurity core rule set (>= 4.0.0 < 4.22.0)

Related

Weakness · CWE (1)

  • CWE-794 Incomplete Filtering of Multiple Instances of Special Elements weakness

References