In CSS Validator less than or equal to commit 54d68a1, there is a cross-site scripting vulnerability in handling URIs. A user would have to click on a specifically crafted validator link to trigger it. This has been patched in commit e5c09a9.

Multiple buffer overflows in the CheckUniqueName function in W3C Amaya Web Browser 10.0.1, and possibly other versions including 11.0.1, might allow remote attackers to execute arbitrary code via "duplicated" attribute value inputs.

Multiple stack-based buffer overflows in W3C Amaya Web Browser 10.0.1 allow remote attackers to execute arbitrary code via (1) a link with a long HREF attribute, and (2) a DIV tag with a long id attribute.

Multiple buffer overflows in World Wide Web Consortium (W3C) Amaya 9.4, and possibly other versions including 8.x before 8.8.5, allow remote attackers to execute arbitrary code via a long value in (1) the COMPACT attribute of the COLGROUP element, (2) the ROWS attribute of the TEXTAREA element, and (3) the COLOR attribute of the LEGEND element; and via other unspecified attack vectors consisting of "dozens of possible snippets."

The HTBoundary_put_block function in HTBound.c for W3C libwww (w3c-libwww) allows remote servers to cause a denial of service (segmentation fault) via a crafted multipart/byteranges MIME message that triggers an out-of-bounds read.

Unknown vulnerability in Jigsaw before 2.2.4 has unknown impact and attack vectors, possibly related to the parsing of the URI.

Cross-site scripting (XSS) vulnerability in W3C Jigsaw Proxy Server before 2.2.1 allows remote attackers to execute arbitrary script via a URL that contains a reference to a nonexistent host followed by the script, which is included in the resulting error message.

Jigsaw 2.2.1 on Windows systems allows remote attackers to use MS-DOS device names in HTTP requests to (1) cause a denial of service using the "con" device, or (2) obtain the physical path of the server using two requests to the "aux" device.

Cross-site scripting (XSS) vulnerability in CERN Proxy Server allows remote attackers to execute script as other users via a link to a non-existent page whose name contains the script, which is inserted into the resulting error page.

The W3C CERN httpd HTTP server allows remote attackers to determine the real pathnames of some commands via a request for a nonexistent URL.