cvedb.io
CVE-2026-21876
CRITICAL · CVSS 9.3
EPSS exploitation probability: 0%
Published 2026-01-08T14:15:57.087 · Last modified 2026-06-17T10:19:04.413

Summary

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 products

owasp — owasp_modsecurity_core_rule_set

Does this affect you?

Add your gear to cvedb and we'll alert you only when owasp ships something exploited.

Check my exposure →

References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.