Bug 2391680 (CVE-2025-40927)

Summary: CVE-2025-40927 perl-cgi-simple: CGI::Simple response splitting flaw
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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An HTTP response splitting flaw was found in the CGI::Simple Perl module. This flaw in CGI::Simple allows HTTP response header injection, which can be used for a reflected cross-site scripting (XSS) attack or an open redirect under certain conditions. Although some validation exists, it can be bypassed using URL-encoded values, allowing an attacker to inject untrusted content into the response via query parameters. As a result, an attacker can inject a line break, such as %0A, into the parameter value, causing the server to split the HTTP response and inject arbitrary headers, or an HTML/JavaScript body, leading to reflected cross-site scripting (XSS), open redirect, or other attacks.
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Bug Depends On: 2391833, 2391834    
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Description OSIDB Bzimport 2025-08-29 01:01:15 UTC 
CGI::Simple versions before 1.282 for Perl has a HTTP response splitting flaw
This vulnerability is a confirmed HTTP response splitting flaw in CGI::Simple that allows HTTP response header injection, which can be used for reflected XSS or open redirect under certain conditions.

Although some validation exists, it can be bypassed using URL-encoded values, allowing an attacker to inject untrusted content into the response via query parameters.



As a result, an attacker can inject a line break (e.g. %0A) into the parameter value, causing the server to split the HTTP response and inject arbitrary headers or even an HTML/JavaScript body, leading to reflected cross-site scripting (XSS), open redirect or other attacks.

The issue documented in CVE-2010-4410 https://www.cve.org/CVERecord?id=CVE-2010-4410 is related but the fix was incomplete.

Impact

By injecting %0A (newline) into a query string parameter, an attacker can:

  *  Break the current HTTP header
  *  Inject a new header or entire body
  *  Deliver a script payload that is reflected in the server’s response
That can lead to the following attacks:

  *  reflected XSS
  *  open redirect
  *  cache poisoning
  *  header manipulation