CVE-2026-100693: Hugo versions from v0.162.0 before v0.166.0 contain a case-sensitive validation flaw in the security.http.urls

Routine

HIGH 8.4UPGRADE

CVE-2026-100693 is a high-severity flaw (CVSS 8.4) affecting hugo. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Hugo versions from v0.162.0 before v0.166.0 contain a case-sensitive validation flaw in the security.http.urls IP-literal deny rule that allows attackers to bypass restrictions. Attackers can use mixed-case URL schemes in resources.GetRemote calls to fetch from restricted IP addresses like localhost.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.4 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.1% (top 97%)
CISA exploited list	No
Weakness	CWE-178
Published	2026-09-26
Last modified	2026-09-30

Publisher (CNA): VulnCheck · Vendor: gohugo

Last updated 2026-09-30 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-26 14:16 UTCPublished CVE record published
2026-09-30 18:18 UTCUpdated Record last modified

gohugo hugo UPGRADE

Affected: >= 0.162.0 and < 0.166.0

Fixed in: 0.166.0

Safe to downgrade to: a release before 0.162.0

1. Check installed version

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

2. UPGRADE to 0.166.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade hugo

Note

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

3. If no update is available yet, DOWNGRADE to a release before 0.162.0 (Debian / Ubuntu)

apt-cache madison hugo sudo apt install hugo=<VERSION_BEFORE_0.162.0> sudo apt-mark hold hugo

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list hugo sudo dnf downgrade hugo-<VERSION_BEFORE_0.162.0> sudo dnf versionlock add hugo

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-100693?

hugo: upgrade to 0.166.0. Exact commands for each OS are on this page.

Is CVE-2026-100693 being exploited?

CVE-2026-100693 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-2026-100693 affect?

CVE-2026-100693 affects hugo. Severity is high (CVSS 8.4). Hugo versions from v0.162.0 before v0.166.0 contain a case-sensitive validation flaw in the security.http.urls IP-literal deny rule that allows attackers to bypass restrictions. Attackers can use mixed-case URL schemes in resources.GetRemot

How urgent is CVE-2026-100693?

Priority 30/100. High severity

Related CVEs

CVE-2026-44301 HIGH 8.1 UPGRADE Hugo is a static site generator
CVE-2026-50134 MEDIUM 5.8 UPGRADE Hugo is a static site generator
CVE-2026-58403 MEDIUM 6.5 UPGRADE Hugo is a static site generator
CVE-2026-58404 MEDIUM 6.8 UPGRADE Hugo is a static site generator
CVE-2026-50133 MEDIUM 6.1 UPGRADE Hugo is a static site generator

References

← Back to latest CVEs