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Vulnerability · Published Aug 29, 2025 · Assigned by CPANSec

CVE-2025-40927CGI::Simple versions 1.281 and earlier for Perl has a HTTP response splitting flaw

High 7.3

In plain English

A high-severity security flaw in CGI::Simple from MANWAR. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.5%top 58.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12libcgi-simple-perl1.280-2+deb12u1DEBIAN-CVE-2025-40927
Debian:13libcgi-simple-perl1.282-1~deb13u1DEBIAN-CVE-2025-40927
Debian:14libcgi-simple-perl1.282-1DEBIAN-CVE-2025-40927
Ubuntu:22.04:LTSlibcgi-simple-perlno fix listedUBUNTU-CVE-2025-40927
Ubuntu:24.04:LTSlibcgi-simple-perlno fix listedUBUNTU-CVE-2025-40927
Ubuntu:25.10libcgi-simple-perlno fix listedUBUNTU-CVE-2025-40927
Ubuntu:26.04:LTSlibcgi-simple-perlno fix listedUBUNTU-CVE-2025-40927

Affected products (as reported)

VendorProductVersions
MANWAR CGI::Simple 0 – before 1.282

Weakness: CWE-113 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

References