CVE-2026-16599: CWE-606 Unchecked input for loop condition in GNU wget
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
CVE-2026-16599: CWE-606 Unchecked input for loop condition in GNU wget
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
CVSS v4.0
Score 5.1medium
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CERT-PL
- Date Reserved
- 2026-07-22T14:11:18.939Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a8da8bcacd9273b4950d980
Added to database: 08/25/2026, 14:37:48 UTC
Last updated: 08/25/2026, 16:22:53 UTC
Views: 5
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