CVE-2026-120639
No CVSS score yet. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
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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.
- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 14th percentile. Scored 2026-11-04. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers (HTTP Request Splitting)
- OWASP Top 10
- A05:2025 Injection
- Published
- Modified
- Record from
- the NVD, synced
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Explain CVE-2026-120639 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-120639?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-120639?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-120639 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12, 13, 14 | libcgi-pm-perl | no fix listed | DEBIAN-CVE-2026-120639 |
From the distributions' data via OSV.dev: the Debian Security Tracker. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian.
Attack patterns (CAPEC)
- CAPEC-31 Accessing/Intercepting/Modifying HTTP Cookies Likelihood: High · Severity: High
- CAPEC-34 HTTP Response Splitting Likelihood: Medium · Severity: High
- CAPEC-85 AJAX Footprinting Likelihood: High · Severity: Low
- CAPEC-105 HTTP Request Splitting Likelihood: Medium · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.