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Fencer Vulns
medium 5.1

CVE-2026-16599 json

Denial of Service in GNU wget

published 2026-08-25 2 mo ago modified 2026-08-28 2 mo ago also EUVD-2026-65494

cvss
5.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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

Patch / fix

  • wget SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 1.25.0-160000.4.1
  • wget SLE Micro 5.5 1.20.3-150000.3.40.1
  • wget SLE Module for Basesystem 15 SP7 1.24.5-150700.3.12.1
  • wget Linux Micro 6.1 1.24.5-slfo.1.1_6.1
  • wget Linux Micro 6.0 1.24.5-5.1
  • wget SLES LTSS Extended Security 12 SP5 1.14-21.31.1

suse advisories SUSE-SU-2026:23975-1SUSE-SU-2026:23991-1SUSE-SU-2026:4074-1SUSE-SU-2026:4053-1SUSE-SU-2026:4049-1SUSE-SU-2026:23520-1

  • wget openSUSE Leap 16.0 1.25.0-160000.4.1
  • wget openSUSE Tumbleweed 1.25.0-7.1

opensuse advisories openSUSE-SU-2026:22011-1openSUSE-SU-2026:11646-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-16599 updated cvss 6.5

wget: wget: Denial of Service via crafted FTP OPIE/S-KEY authentication challenge

  • Red Hat Enterprise Linux 6 wget Red Hat Enterprise Linux 7 wget Red Hat Enterprise Linux 8 wget Red Hat Enterprise Linux 9 wget Red Hat Enterprise Linux 10 wget
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.1 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
CNA 4.0 5.1 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • GNU wget

Classification

Weakness
  • CWE-606 Unchecked Input for Loop Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.