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CVE-2025-40927                                       CPAN Security Group
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         CVE ID:  CVE-2025-40927
   Distribution:  CGI-Simple
       Versions:  before 1.282

       MetaCPAN:  https://metacpan.org/dist/CGI-Simple
       VCS Repo:  https://github.com/manwar/CGI--Simple

CGI::Simple versions 1.281 and earlier for Perl has a HTTP response
splitting flaw

Description
-----------
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

Problem types
-------------
- CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers
   ('HTTP Request/Response Splitting')

Solutions
---------
Upgrade CGI::Simple to version 1.282 or higher

References
----------
https://metacpan.org/release/MANWAR/CGI-Simple-1.281/source/lib/CGI/Simple.pm#L1031-1035
https://metacpan.org/release/MANWAR/CGI-Simple-1.281/diff/MANWAR/CGI-Simple-1.282/lib/CGI/Simple.pm
https://owasp.org/www-community/attacks/HTTP_Response_Splitting
https://datatracker.ietf.org/doc/html/rfc7230#section-3
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-2320
https://rt.perl.org/Public/Bug/Display.html?id=21951

Credits
-------
Maxim Kosenko, finder