AUGUST 4, 2026
Live Feed
Back to database
Case File

CVE-2026-21876

CRITICAL · CVSS 9.3 EPSS 13.12% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-01-08 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.3. Public exploit code or proof-of-concept references have been detected in its references. Its EPSS score suggests a 13.1% probability of exploitation in the next 30 days.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-21876
Severity
CRITICAL
CVSS
9.3
EPSS
13.12%

Original NVD 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.

Related CVEs

Other vulnerabilities affecting the same vendor(s)