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.
References
| Link | Resource |
|---|---|
| https://github.com/coreruleset/coreruleset/commit/2a8c63512811c5dd74472becebb79a783e68ff02 | Patch |
| https://github.com/coreruleset/coreruleset/pull/4546 | Issue Tracking Patch |
| https://github.com/coreruleset/coreruleset/pull/4547 | Issue Tracking Patch |
| https://github.com/coreruleset/coreruleset/pull/4548 | Patch |
| https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9 | Product Release Notes |
| https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0 | Product Release Notes |
| https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w | Mitigation Patch Vendor Advisory |
| http://seclists.org/fulldisclosure/2026/Apr/0 | Mailing List Third Party Advisory |
| http://www.openwall.com/lists/oss-security/2026/03/29/2 | Mailing List Third Party Advisory |
| http://www.openwall.com/lists/oss-security/2026/04/18/4 |
Configurations
Configuration 1 (hide)
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History
18 Apr 2026, 20:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
|
| References | () 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 - Patch | |
| References | () https://github.com/coreruleset/coreruleset/pull/4546 - Issue Tracking, Patch | |
| References | () https://github.com/coreruleset/coreruleset/pull/4547 - Issue Tracking, Patch | |
| References | () https://github.com/coreruleset/coreruleset/pull/4548 - Patch | |
| References | () https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9 - Product, Release Notes | |
| References | () 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 - Vendor Advisory, Mitigation, Patch | |
| References | () http://seclists.org/fulldisclosure/2026/Apr/0 - Mailing List, Third Party Advisory | |
| References | () 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 |
|
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
