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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| unaffected |
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Project Subscriptions
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No advisories yet.
Solution
Upgrade to CGI 5.00 or later.
Workaround
For deployments that cannot upgrade, strip X-Forwarded-Host at the web server or proxy unless it sets the header itself, and validate Host.
Wed, 04 Nov 2026 00:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | CGI 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. | |
| Title | CGI versions before 5.00 for Perl trust the client X-Forwarded-Host header in url, self_url, virtual_host and virtual_port | |
| Weaknesses | CWE-348 CWE-601 |
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| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: CPANSec
Published:
Updated: 2026-11-03T23:40:04.604Z
Reserved: 2026-11-02T17:40:07.895Z
Link: CVE-2026-120633
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-11-04T00:17:24.450
Modified: 2026-11-04T00:17:24.450
Link: CVE-2026-120633
Redhat
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OpenCVE Enrichment
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