Package Instance

Improper Restriction of XML External Entity Reference
A flaw in libxml2 allows remote XML entity inclusion with default parser flags (i.e., when the caller did not request entity substitution, DTD validation, external DTD subset loading, or default DTD attributes). Depending on the context, this may expose a higher-risk attack surface in libxml2 not usually reachable with default parser flags, and expose content from local files, HTTP, or FTP servers (which might be otherwise unreachable).

Use After Free
Use-after-free vulnerability in libxml2, as used in Google Chrome, allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to the XPointer range-to function.

Loop with Unreachable Exit Condition ('Infinite Loop')
parser.c in libxml2 does not prevent infinite recursion in parameter entities.

Improper Restriction of Operations within the Bounds of a Memory Buffer
parser.c in libxml2 mishandles parameter-entity references because the NEXTL macro calls the xmlParserHandlePEReference function in the case of a '%' character in a DTD name.

Out-of-bounds Read
The htmlParseTryOrFinish function in HTMLparser.c in libxml2 allows attackers to cause a denial of service (buffer over-read) or information disclosure.

Improper Restriction of Operations within the Bounds of a Memory Buffer
A buffer overflow was discovered in libxml2 . The function xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a char buffer 'buf' of size 'size'. The variable len is assigned strlen(buf). If the content->type is XML_ELEMENT_CONTENT_ELEMENT, then (i) the content->prefix is appended to buf (if it actually fits) whereupon (ii) content->name is written to the buffer. However, the check for whether the content->name actually fits also uses 'len' rather than the updated buffer length strlen(buf). This allows us to write about "size" many bytes beyond the allocated memory. This vulnerability causes programs that use libxml2, such as PHP, to crash.

Improper Restriction of XML External Entity Reference
libxml2, as used in XMLSec and other products, does not offer a flag directly indicating that the current document may be read but other files may not be opened, which makes it easier for remote attackers to conduct XML External Entity (XXE) attacks via a crafted document.

Improper Restriction of Operations within the Bounds of a Memory Buffer
libxml2 is vulnerable to a stack-based buffer overflow. The function xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a char buffer 'buf' of size 'size'. At the end of the routine, the function may strcat two more characters without checking whether the current strlen(buf) + 2 < size. This vulnerability causes programs that use libxml2, such as PHP, to crash.