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The vulnerability (CVE-2025-XXXX) in Apache Tomcat arises due to improper case sensitivity handling in the CGI servlet. Attackers can bypass security constraints applied to the `pathInfo` component of a URI mapped to the CGI servlet by manipulating letter casing. For example, if a constraint blocks /admin/, an attacker could access `/ADMIN/` or `/AdMiN/` to evade restrictions. This affects Tomcat versions 9.0.0.M1 to 9.0.104, 10.1.0-M1 to 10.1.40, and 11.0.0-M1 to 11.0.6. The flaw stems from inconsistent case normalization when comparing URIs against security constraints.
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Platform: Apache Tomcat
Version: 9.0.0-11.0.6
Vulnerability: Constraint bypass
Severity: Low
Date: May 29, 2025
Prediction: Patch by June 15, 2025
What Undercode Say:
Exploitation:
- Craft HTTP requests with mixed-case paths (e.g.,
/AdMiN/script.cgi).
2. Bypass `web.xml` constraints via case variation.
Mitigation:
1. Upgrade to Tomcat 9.0.105, 10.1.41, or 11.0.7.
2. Apply case-insensitive regex filters in `web.xml`:
<security-constraint> <web-resource-collection> <url-pattern>(?i)/admin/.</url-pattern> </web-resource-collection> </security-constraint>
Detection:
1. Scan logs for mixed-case CGI requests:
grep -Ei "GET /[a-z]+[A-Z]+[a-z]+" catalina.out
Workaround:
1. Disable CGI servlet if unused:
<servlet-mapping> <servlet-name>cgi</servlet-name> <url-pattern>/disabled</url-pattern> </servlet-mapping>
Analytics:
- Attack Vector: Low complexity, no privileges required.
- Impact: Partial confidentiality breach.
- Patch Adoption: Expected within 30 days.
References:
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
