CVE-2026-33691

6.8 MEDIUM
Published: April 02, 2026 Modified: April 07, 2026
View on 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 3.3.9 and 4.25.0, a bypass was identified in OWASP CRS that allows uploading files with dangerous extensions (.php, .phar, .jsp, .jspx) by inserting whitespace padding in the filename (e.g. photo. php or shell.jsp ). The affected rules do not normalize whitespace before evaluating the file extension regex, so the dot-extension check fails to match. This issue has been patched in versions 3.3.9 and 4.25.0.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/coreruleset/coreruleset/pull/4546
Source: security-advisories@github.com
Issue Tracking Patch
https://github.com/coreruleset/coreruleset/pull/4547
Source: security-advisories@github.com
Issue Tracking Patch
https://github.com/coreruleset/coreruleset/pull/4548
Source: security-advisories@github.com
Patch
https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9
Source: security-advisories@github.com
Product Release Notes
https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0
Source: security-advisories@github.com
Product Release Notes
https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w
Source: security-advisories@github.com
Vendor Advisory Mitigation Patch
http://seclists.org/fulldisclosure/2026/Apr/0
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/03/29/2
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory

9 reference(s) from NVD

Quick Stats

CVSS v3 Score
6.8 / 10.0
EPSS (Exploit Probability)
0.1%
21th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

owasp