CGI versions before 5.00 for Perl trust the client X-Forwarded-Host header in url, self_url, virtual_host and virtual_port

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-120633
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-04 00:17:24 UTC
Updated2026-11-04 18:42:35 UTC
DescriptionCGI versions before 5.00 for Perl trust the client X-Forwarded-Host header in url, self_url, virtual_host and virtual_port. These take the host name and port from the X-Forwarded-Host request header when present, and otherwise from Host, without validating either. The URLs from url and self_url are the default redirect location and the start_html(-base=>1) base href, and the default start_form action when REQUEST_URI is not set. A client can poison shared caches, and URLs the application stores or sends, with redirects, links and scripts that point at a host it controls.

Risk And Classification

Problem Types: CWE-348 | CWE-601 | CWE-348 CWE-348 Use of Less Trusted Source | CWE-601 CWE-601 URL Redirection to Untrusted Site ('Open Redirect')

References

ReferenceSourceLinkTags
metacpan.org/release/LEEJO/CGI-5.00/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
metacpan.org/release/LEEJO/CGI-4.72/source/lib/CGI.pm 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
github.com/leejo/CGI.pm/commit/d76752a5e8dfd365b0fe3a0b9a7da6c054e856af.... 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to CGI 5.00 or later.

Workarounds

CNA: For deployments that cannot upgrade, strip X-Forwarded-Host at the web server or proxy unless it sets the header itself, and validate Host.

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