CVE-2026-16599
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
- Score
- CVSS 4.0 5.1 Medium
- Status
- Deferred - cvd@cert.pl
- Published
- 2026-08-25
- Last modified
- 2026-08-25
- Weaknesses
- CWE-606
Affected products
References
- https://cert.pl/en/posts/2026/08/CVE-2026-16599
- https://gitlab.com/gnuwget/wget
- https://gitlab.com/gnuwget/wget/-/commit/e9697d98e7249b0f68a6be040a4f3dcc5bc101fa
