Client hang via unbounded FTP authentication loop
Published Aug 25, 2026 · Updated Aug 25, 2026
Denial of service in GNU Wget 1.25.0 and earlier allows remote attackers to hang the client via a crafted FTP OPIE challenge. In ftp_login, a server-supplied sequence number is passed directly to skey_response as an MD5 loop count without an upper bound. A user must direct Wget to the malicious FTP server, or man-in-the-middle attackers must intercept FTP traffic; network timeouts do not stop the CPU loop.
Summary
What happened
Denial of service in GNU Wget 1.25.0 and earlier allows remote attackers to hang the client via a crafted FTP OPIE challenge. In ftp_login, a server-supplied sequence number is passed directly to skey_response as an MD5 loop count without an upper bound. A user must direct Wget to the malicious FTP server, or man-in-the-middle attackers must intercept FTP traffic; network timeouts do not stop the CPU loop.
The record
- CVE
- CVE-2026-16599
- Published
- Aug 25, 2026
- Updated
- Aug 25, 2026
- Vendor
- The GnuPG Project
- Product
- GNU Wget
- Classifications
- CWE-606, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=1.25.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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