CVE-2026-21876 describes a bug in the OWASP Core Rule Set (CRS) affecting versions prior to 4.22.0 and 3.3.8. This vulnerability, specifically in rule 922110, allows attackers to bypass charset validation in multipart requests by exploiting how capture variables are overwritten, potentially missing malicious charsets in earlier parts. With a CVSS score of 5.3 (MEDIUM), it has a network attack vector, low attack complexity, and a potential impact of low integrity. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or KEV listing, though it has garnered significant community discussion with 15 mentions.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 3.3.8CPE matchmatch criteria | cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:* | ||
>= 4.0.0, < 4.22.0CPE matchmatch criteria | cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.