CVE-2026-120635CWE-436

CVE-2026-120635: vulnerability in CGI

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

Published

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3Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackepss 0.2%
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.
Affected products
CGI
Related CVEs — CGI

In the same product, most dangerous first.

CVE-2026-120645—CGI versions before 5.00 for Perl allow denial of service via submitted values used as a regex for optgroup selection in scrolling_listEPSS 0.4%CVE-2026-120631—CGI::Cookie versions from 4.67 before 5.00 for Perl allow denial of service via the client cookie expires value used as a regex in parseEPSS 0.4%CVE-2026-120639—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_pushEPSS 0.2%CVE-2026-120636—CGI versions before 5.00 for Perl allow open redirects and script injection via URLs built from REQUEST_URI in url and start_formEPSS 0.2%CVE-2026-120648—CGI versions before 5.00 for Perl allow HTML injection via text containing --> in commentEPSS 0.2%CVE-2026-120643—CGI versions from 4.62 before 5.00 for Perl allow cross-site scripting via a raw apostrophe in URLs returned by url and self_urlEPSS 0.2%