GNU wget is vulnerable to denial of service in its FTP OPIE/S-KEY authentication functionality. The server-supplied sequence number from the FTP challenge line is used as an iteration count for an MD5 key-derivation loop without any upper bound validation. A malicious FTP server or a network attacker positioned to intercept FTP traffic can send a crafted OPIE challenge with a sequence number near INT_MAX, causing wget to perform up to approximately 2.1 billion MD5 computations and suspend for some time. The --timeout option does not mitigate this because it applies only to network I/O, not CPU computation.
This issue was fixed in commit e96
USN-8543-1 fixed vulnerabilities in Wget. The update for CVE-2026-58472
was incomplete and could introduce a regression. This update fixes the
problem.
We apologize for the inconvenience.
Original advisory details:
It was discovered that Wget mishandled semicolons in the userinfo
subcomponent of a URL. A remote attacker could possibly use this issue
to trick a user into connecting to a different host than intended. This
issue only affected Ubuntu 14.04 LTS. (CVE-2024-38428)
It was discovered that Wget incorrectly handled Metalink documents
containing a whitespace-only URL. A remote attacker could possibly use
this issue to cause a
GNU Wget does not validate the IP address provided by an FTP PASV response while operating in FTP passive mode. A malicious FTP server, or an HTTP server that redirects to an FTP URL, can exploit this behavior to redirect Wget’s data connection to an arbitrary IP address and port. This allows an attacker to forge server-side requests (SSRF) from the machine running Wget, potentially accessing localhost services or internal network resources.
GNU Wget 1.25.0 Heap Buffer Overflow via HTML Attribute Encoding
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 1.25.0 Heap Buffer Overflow via convert_fname() in url.c
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 1.25.0 Integer Overflow via Content-Range Header Parsing
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 1.25.0 Heap Buffer Underread via Metalink URL Parsing
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.
GNU Wget is vulnerable to an SSRF attack when accessing partially-user-controlled shorthand URLs
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.