CVE-2026-33691
MEDIUMEPSS 80th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
Exploit Intelligence
Elevated risk: more likely to be exploited than 80% of all known CVEs.
References
Related Vulnerabilities
Other CWE-178 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-27636 | Medium | 5.6 | 80% | - | Fix |
| CVE-2021-24347 | High | 8.8 | 52% | - | Fix |
| CVE-2020-12812 | Critical | 9.8 | 49% | KEV + Ransom | Fix |
| CVE-2003-0411 | High | 7.5 | 25% | - | - |
| CVE-2018-9845 | Critical | 9.8 | 13% | - | Fix |
| CVE-2001-0766 | Critical | 9.8 | 8.2% | - | - |
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-18.