# CVE-2025-40927: libcgi-simple-perl: CGI::Simple versions before 1.282 for Perl has a HTTP response splitting flaw This vulnerability is a confirmed HTTP...

CVE-2025-40927 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2025-40927, released August 29, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-40927
- Priority: High
- CVSS: 7.3 (high)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 29, 2025

## 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

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libcgi-simple-perl Debian 12.15 (bookworm) | 1.280-2+deb12u1 | [DEBIAN-CVE-2025-40927](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40927.md) | Aug 29, 2025 |
| Linux | libcgi-simple-perl Debian 13.5 (trixie) | 1.282-1~deb13u1 | [DEBIAN-CVE-2025-40927](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40927.md) | Aug 29, 2025 |
| Linux | libcgi-simple-perl Debian 14 | 1.282-1 | [DEBIAN-CVE-2025-40927](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40927.md) | Aug 29, 2025 |
| Linux | perl-CGI-Simple Fedora 43 | 1:1.282-1.fc43 | [FEDORA-2025-3DD97ED203](https://patchblox.com/security/data/fix/linux/fedora-2025-3dd97ed203.md) | Dec 2, 2025 |

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