CVE-2026-1858: wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU)

Q: How do I fix CVE-2026-1858?

wget2: upgrade to newer than 2.2.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-1858 being exploited?

CVE-2026-1858 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-1858 affect?

CVE-2026-1858 affects wget2. Severity is medium (CVSS 4.8). 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 s

Q: How urgent is CVE-2026-1858?

Priority 28/100. Public exploit reference; Remotely exploitable, no login, no user action

This week

MEDIUM 4.8REMOTEUPGRADE

CVE-2026-1858 is a medium-severity flaw (CVSS 4.8) affecting wget2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 95%)
CISA exploited list	No
Weakness	CWE-20
Published	2026-04-29
Last modified	2026-10-26

Publisher (CNA): Tenable Network Security, Inc. · Vendor: gnu

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-29 21:16 UTCPublished CVE record published
2026-10-26 20:10 UTCUpdated Record last modified

gnu wget2 UPGRADE

Affected: <= 2.2.1

Fixed in: newer than 2.2.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy wget2 || rpm -q wget2 || wget2 --version

2. UPGRADE to newer than 2.2.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade wget2

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade wget2

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-1858?

wget2: upgrade to newer than 2.2.1. Exact commands for each OS are on this page.

Is CVE-2026-1858 being exploited?

CVE-2026-1858 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-1858 affect?

CVE-2026-1858 affects wget2. Severity is medium (CVSS 4.8). 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 s

How urgent is CVE-2026-1858?

Priority 28/100. Public exploit reference; Remotely exploitable, no login, no user action

References

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