How severe is CVE-2026-35166?

No CVSS score has been assigned to CVE-2026-35166 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-35166?

CVE-2026-35166 affects the following packages: github.com/gohugoio/hugo (Go). Ecosystems affected: Go.

How do I fix CVE-2026-35166?

Update github.com/gohugoio/hugo to 0.159.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35166 is resolved across your whole dependency graph.

How do I detect CVE-2026-35166 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gohugoio/hugo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-35166 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-35166 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-35166 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-35166?

CVE-2026-35166 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 8th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-35166?

CVE-2026-35166 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-35166 published, and has it been updated?

CVE-2026-35166 was published on April 6, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2026-35166 — hugo

Fix: gohugoio/hugo@479fe6c

CVE-2026-35166 is a Cross-site Scripting (XSS) vulnerability in github.com/gohugoio/hugo. A fix is available for github.com/gohugoio/hugo — see the affected versions and patch details below.

Hugo does not properly escape some Markdown links

Also known asGHSA-mcv8-8m8x-48pgGO-2026-5504

Published

Apr 6, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-35166.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs8th percentile — riskier than 8% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/gohugoio/hugo

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Links and image links in the default markdown to HTML renderer are not properly escaped. Hugo users who trust their Markdown content or have custom render hooks for links and images are not affected.

Patches

Patched in v0.159.2

Workarounds

Create custom render hooks for links and images in a Hugo theme/project.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/gohugoio/hugo`	≥ 0.60.0&&< 0.159.2	0.159.2`go get github.com/gohugoio/hugo@v0.159.2`

Affected Products

1 product · 3 configurations

Application

hugogohugo

≥ 0.60.0 && < 0.159.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gohugoio/hugo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/gohugoio/hugo to 0.159.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35166 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Workaround published by Red Hat

To mitigate this issue, ensure that all markdown content processed by Hugo originates from trusted sources. Alternatively, implement custom render hooks for links and images within Hugo to ensure proper escaping, as this configuration prevents exploitation.

Source: Red Hat security advisory for CVE-2026-35166 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Hardened Images	`hugo-main-0.160.1-2.hum1`	RHSA-2026:7848

Frequently Asked Questions

### Impact Links and image links in the default markdown to HTML renderer are not properly escaped. Hugo users who trust their Markdown content or have custom render hooks for links and images are not affected. ### Patches Patched in v0.159.2 ### Workarounds Create custom render hooks for links and images in a Hugo theme/project.

O3 Security · Impact-Aware SCA

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