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
References6
- cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-2320
- datatracker.ietf.org/doc/html/rfc7230#section-3
- metacpan.org/release/MANWAR/CGI-Simple-1.281/diff/MANWAR/CGI-Si…
- metacpan.org/release/MANWAR/CGI-Simple-1.281/source/lib/CGI/Sim…
- owasp.org/www-community/attacks/HTTP_Response_Splitting
- rt.perl.org/Public/Bug/Display.html?id=21951
Metrics
- CVSS 3.1
-
7.3
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - EPSS — exploit probability
- 0% percentile: 42 · as of 8 November 2026
- CWE
- CWE-113
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.