Vulnerability · Published Aug 25, 2026 · Assigned by CERT-PL
CVE-2026-16599Denial of Service in GNU wget
Medium 5.1
In plain English
A medium-severity security flaw in wget from GNU. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities).
Official 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
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | wget | no fix listed | DEBIAN-CVE-2026-16599 |
| Debian:13 | wget | no fix listed | DEBIAN-CVE-2026-16599 |
| Debian:14 | wget | no fix listed | DEBIAN-CVE-2026-16599 |
| Ubuntu:22.04:LTS | wget | no fix listed | UBUNTU-CVE-2026-16599 |
| Ubuntu:24.04:LTS | wget | no fix listed | UBUNTU-CVE-2026-16599 |
| Ubuntu:26.04:LTS | wget | no fix listed | UBUNTU-CVE-2026-16599 |
| Ubuntu:26.10 | wget | no fix listed | UBUNTU-CVE-2026-16599 |
Affected products (as reported)
Weakness: CWE-606 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N