GNU Wget through 1.25.0, fixed in commit dd692d9, contains a heap buffer overflow vulnerability in the html_quote_string() function in src/convert.c that allows a remote attacker to trigger memory corruption by supplying a crafted HTML attribute with a large number of characters requiring entity encoding. A server-supplied HTML attribute causes a signed integer counter to overflow during output size accumulation, resulting in an undersized heap allocation and subsequent heap buffer overflow during the copy phase.

GNU Wget through 1.25.0, fixed in commit c2640fe, contains a heap buffer overflow vulnerability in the convert_fname() function within src/url.c that allows remote attackers to trigger memory corruption through a server-supplied filename requiring character set conversion. When the output buffer is too small during iconv E2BIG reallocation, the reallocation logic miscalculates the remaining space, leading to a heap buffer overflow that can be exploited via a maliciously crafted server response.

GNU Wget through 1.25.0, fixed in commit 43d3ba9, contains an integer overflow vulnerability in the parse_content_range() function within src/http.c that allows server-controlled values to cause signed integer arithmetic to overflow. Attackers can supply malicious Content-Range header values to trigger undefined behavior and download desynchronization in the affected client.

GNU Wget through 1.25.0, fixed in commit 37a40fc, contains a heap buffer underread vulnerability in the clean_metalink_string() function within src/metalink.c that allows a malicious server to trigger memory corruption by serving a Metalink document containing a whitespace-only URL. Attackers can cause the function to decrement a pointer past the start of the buffer when processing an all-whitespace Metalink URL, potentially leading to abnormal program behavior.

url.c in GNU Wget through 1.24.5 mishandles semicolons in the userinfo subcomponent of a URI, and thus there may be insecure behavior in which data that was supposed to be in the userinfo subcomponent is misinterpreted to be part of the host subcomponent.

Applications that use Wget to access a remote resource using shorthand URLs and pass arbitrary user credentials in the URL are vulnerable. In these cases attackers can enter crafted credentials which will cause Wget to access an arbitrary host.