SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2025-40927

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…

HIGH 7.3EPSS 0.47%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.47%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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

CVSS 3.1
7.3 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS
0.47% probability · 39th percentile
CISA KEV
Not listed
Weakness
CWE-113
Source
9b29abf9-4ab0-4765-b253-1875cd9b441e

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.