CVE-2026-33691 describes a medium-severity bypass vulnerability in OWASP Core Rule Set (CRS) versions prior to 3.3.9 and 4.25.0. This flaw allows attackers to upload dangerous file types (e.g., .php, .jsp) by inserting whitespace padding in filenames, circumventing the WAF's extension checks. Rated with a CVSS score of 6.8, it carries a high impact on integrity (I:H) with high attack complexity (AC:H), but requires no user interaction or privileges. While there is no evidence of active exploitation (KEV: No) or publicly available exploit code, the vulnerability has garnered some community discussion and media coverage.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 3.3.9CPE matchmatch criteria | cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:* | ||
>= 4.0.0, < 4.25.0CPE 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:H/PR:N/UI:N/S:C/C:N/I:H/A:N
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.
The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.