CGI CVE-2026-120639

HTTP Response Splitting (CWE-113)

2026-11-04 9b29abf9-4ab0-4765-b253-1875cd9b441e

Code Injection

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Vulnerability Assessment

Weakness

CWE

CWE-113

OWASP Top 10:2025

A05:2025 - Injection

ASVS 5.0

V1 - Encoding and Sanitization HTTP response header sanitization

Monitor Track and reassess. Why: No CVSS yet + weak signal (CWE or non-zero EPSS).

No patch listed yet

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AnalysisCVE.org

CGI versions before 5.00 for Perl allow HTTP header injection via entity decoding after the newline check in header and unchecked values in multipart_start and do_push.

With autoEscape off, header decodes HTML entities in extra header values after its newline check, so an encoded CR or LF reaches the response. multipart_start does not check header values for newlines, and do_push does not check the type it prints in each part.

An application that passes request data into these header values can be made to add headers or split the response.

Affects your stack

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Exploit and PoC references, threat intelligence from 22 sources

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Threat Intelligence Overview

Data Quality

2 sources

Confidence: Low

CVE.org

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity Not scored yet

CISA KEV No

Public POC No

EPSS N/A

Patch available No

Active threat No

Deciding rule

No CVSS yet + weak signal (CWE or non-zero EPSS)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.