Heap-based buffer overflow in the ParseValue function in lexer.c in tidy before 4.9.31 allows remote attackers to cause a denial of service (crash) via vectors involving a command character in an href.

The ParseValue function in lexer.c in tidy before 4.9.31 allows remote attackers to cause a denial of service (crash) via vectors involving multiple whitespace characters before an empty href, which triggers a large memory allocation.

In Tidy 5.5.31, the IsURLCodePoint function in attrs.c allows attackers to cause a denial of service (Segmentation Fault), as demonstrated by an invalid ISALNUM argument.

In Tidy 5.7.0, the prvTidyTidyMetaCharset function in clean.c allows attackers to cause a denial of service (Segmentation Fault), because the currentNode variable in the "children of the head" processing feature is modified in the loop without validating the new value.

An issue in HTACG HTML Tidy v5.7.28 allows attacker to execute arbitrary code via the -g option of the CleanNode() function in gdoc.c.

A vulnerability classified as problematic has been found in HTACG tidy-html5 5.8.0. Affected is the function defaultAlloc of the file src/alloc.c. The manipulation leads to memory leak. It is possible to launch the attack on the local host. The exploit has been disclosed to the public and may be used.