CVE-2026-33691

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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:*
cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:*

History

18 Apr 2026, 20:16

Type Values Removed Values Added
References
  • () http://www.openwall.com/lists/oss-security/2026/04/18/4 -
References () https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w - Vendor Advisory, Mitigation, Patch () https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w - Mitigation, Patch, Vendor Advisory

07 Apr 2026, 14:02

Type Values Removed Values Added
CPE cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:*
First Time Owasp owasp Modsecurity Core Rule Set
Owasp
References () https://github.com/coreruleset/coreruleset/commit/2a8c63512811c5dd74472becebb79a783e68ff02 - () https://github.com/coreruleset/coreruleset/commit/2a8c63512811c5dd74472becebb79a783e68ff02 - Patch
References () https://github.com/coreruleset/coreruleset/pull/4546 - () https://github.com/coreruleset/coreruleset/pull/4546 - Issue Tracking, Patch
References () https://github.com/coreruleset/coreruleset/pull/4547 - () https://github.com/coreruleset/coreruleset/pull/4547 - Issue Tracking, Patch
References () https://github.com/coreruleset/coreruleset/pull/4548 - () https://github.com/coreruleset/coreruleset/pull/4548 - Patch
References () https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9 - () https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9 - Product, Release Notes
References () https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0 - () https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0 - Product, Release Notes
References () https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w - () https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w - Vendor Advisory, Mitigation, Patch
References () http://seclists.org/fulldisclosure/2026/Apr/0 - () http://seclists.org/fulldisclosure/2026/Apr/0 - Mailing List, Third Party Advisory
References () http://www.openwall.com/lists/oss-security/2026/03/29/2 - () http://www.openwall.com/lists/oss-security/2026/03/29/2 - Mailing List, Third Party Advisory

03 Apr 2026, 06:16

Type Values Removed Values Added
References
  • () http://seclists.org/fulldisclosure/2026/Apr/0 -

02 Apr 2026, 16:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-04-02 16:16

Updated : 2026-04-18 20:16


NVD link : CVE-2026-33691

Mitre link : CVE-2026-33691

CVE.ORG link : CVE-2026-33691


JSON object : View

Products Affected

owasp

  • owasp_modsecurity_core_rule_set
CWE
CWE-178

Improper Handling of Case Sensitivity