Vulnerability Description
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 e9697d98e7249b0f68a6be040a4f3dcc5bc101fa
Related Weaknesses (CWE)
References
- https://cert.pl/en/posts/2026/08/CVE-2026-16599
- https://gitlab.com/gnuwget/wget
- https://gitlab.com/gnuwget/wget/-/commit/e9697d98e7249b0f68a6be040a4f3dcc5bc101f
FAQ
What is CVE-2026-16599?
CVE-2026-16599 is a documented vulnerability. 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...
How severe is CVE-2026-16599?
CVSS scoring is not yet available for CVE-2026-16599. Check NVD for updates.
Is there a patch for CVE-2026-16599?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.