CVE-2026-16599

NameCVE-2026-16599
DescriptionGNU 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
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
wget (PTS)bullseye1.21-1+deb11u1vulnerable
bullseye (security)1.21-1+deb11u2vulnerable
bookworm1.21.3-1+deb12u1vulnerable
trixie1.25.0-2vulnerable
forky, sid1.25.0-3vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
wgetsource(unstable)(unfixed)

Notes

https://cert.pl/en/posts/2026/08/CVE-2026-16599/
Fixed by: https://gitlab.com/gnuwget/wget/-/commit/e9697d98e7249b0f68a6be040a4f3dcc5bc101fa

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