CVE-2026-33691

Published Apr 2, 2026

Last updated 3 months ago

CVSS medium 6.8

API

Overview

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.
Source: security-advisories@github.com
NVD status: Modified
Products: owasp_modsecurity_core_rule_set

Risk scores

CVSS 3.1

Type: Primary
Base score: 7.5
Impact score: 3.6
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: HIGH

Weaknesses

security-advisories@github.com: CWE-178

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "33F8A888-1ED5-40BC-B1B9-7AA88411B0E0",
            "versionEndExcluding": "3.3.9",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "8822CE75-E018-4576-B30B-A25A1A2F60E0",
            "versionEndExcluding": "4.25.0",
            "versionStartIncluding": "4.0.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.

Overview

Risk scores

CVSS 3.1

Weaknesses

Social media

Configurations

Related CVEs

References