Vulnerability · Published Apr 29, 2026 · Assigned by tenable
CVE-2026-1858wget2 Improper Certificate Validation
Medium 4.8
In plain English
A medium-severity improper input validation in wget2 from gnu. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).
Severity (CVSS 3.1)4.8Medium
Exploit odds (30 days)0.2%top 95.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | wget2 | no fix listed | DEBIAN-CVE-2026-1858 |
| Debian:13 | wget2 | no fix listed | DEBIAN-CVE-2026-1858 |
| Debian:14 | wget2 | no fix listed | DEBIAN-CVE-2026-1858 |
| Ubuntu:22.04:LTS | wget2 | no fix listed | UBUNTU-CVE-2026-1858 |
| Ubuntu:24.04:LTS | wget2 | no fix listed | UBUNTU-CVE-2026-1858 |
| Ubuntu:25.10 | wget2 | no fix listed | UBUNTU-CVE-2026-1858 |
| Ubuntu:26.04:LTS | wget2 | no fix listed | UBUNTU-CVE-2026-1858 |
| Ubuntu:26.10 | wget2 | no fix listed | UBUNTU-CVE-2026-1858 |
Affected products (as reported)
Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N