CGI versions before 5.00 for Perl allow form fields to be smuggled past proxies and WAFs via multipart parsing that differs from the RFCs.

The multipart/form-data parser matches the boundary anywhere rather than at the start of a line, uses the boundary without its leading -- for some client-supplied User-Agent values, finds the Content-Disposition name and filename inside the quoted values of other parameters, and corrupts parts when the boundary nears the 4096-byte read size.
Advisories

No advisories yet.

Fixes

Solution

Upgrade to CGI 5.00 or later.


Workaround

No workaround given by the vendor.

History

Wed, 04 Nov 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-444
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

threat_severity

Moderate


Wed, 04 Nov 2026 00:00:00 +0000

Type Values Removed Values Added
Description CGI versions before 5.00 for Perl allow form fields to be smuggled past proxies and WAFs via multipart parsing that differs from the RFCs. The multipart/form-data parser matches the boundary anywhere rather than at the start of a line, uses the boundary without its leading -- for some client-supplied User-Agent values, finds the Content-Disposition name and filename inside the quoted values of other parameters, and corrupts parts when the boundary nears the 4096-byte read size.
Title CGI versions before 5.00 for Perl allow form fields to be smuggled past proxies and WAFs via multipart parsing that differs from the RFCs
Weaknesses CWE-436
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-11-03T23:40:15.070Z

Reserved: 2026-11-02T17:40:25.384Z

Link: CVE-2026-120635

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-04T00:17:24.730

Modified: 2026-11-04T00:17:24.730

Link: CVE-2026-120635

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-11-03T23:40:15Z

Links: CVE-2026-120635 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-11-04T15:00:19Z

Weaknesses