جزئیات آسیب‌پذیری

HTTP::Body versions before 1.23_01 for Perl drop mixed-case percent escapes from urlencoded form fields instead of decoding them. The decode table holds only the all-lowercase and all-uppercase spelling of each hex pair, while the escape pattern matches either case. An escape such as %aB finds no entry and is replaced with nothing, joining the bytes on either side. Hex digits in percent escapes are case-insensitive, and conforming decoders return the byte. A remote attacker can send a field name or value that a conforming decoder in front of the application reads differently, so that pass%aBword reaches the application as password.

• https://github.com/libwww-perl/HTTP-Body/commit/336f1a23b4115a5cbeb546f36df5af62c90bdc0d.patch patch
• https://metacpan.org/release/GETTY/HTTP-Body-1.24/changes release-notes
• https://www.rfc-editor.org/rfc/rfc3986#section-2.1