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.

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.

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.

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.

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.