# CVE-2026-35166: Hugo does not properly escape some Markdown links

> Attackers can inject malicious scripts via unescaped Markdown links in Hugo-generated sites, affecting users who do not trust their content.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Apr 2026
- **Updated:** 6 Apr 2026
- **Also known as:** DEBIAN-CVE-2026-35166, GHSA-mcv8-8m8x-48pg, GO-2026-5504, JLSEC-2026-792, RHSA-2026:7848, UBUNTU-CVE-2026-35166

## What is CVE-2026-35166?

CVE-2026-35166 is a medium-severity cross-site scripting vulnerability in gohugoio hugo, published on 6 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Hugo is a static site generator. From 0.60.0 to before 0.159.2, 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. This vulnerability is fixed in 0.159.2.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-35166?

3 open source packages ship an affected version, including github.com/gohugoio/hugo. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/gohugoio/hugo` | Go | From 0.60.0 | 0.159.2 |
| `github.com/gohugoio/hugo` | Go | From 0.60.0 | 0.159.2 |
| `github.com/gohugoio/hugo` | Go | From 0.60.0 | 0.159.2 |
| `hugo` | Red Hat:hummingbird:1 | All versions | 0:0.160.1-2.hum1 |

Products: Gohugo Hugo.

## How do I fix CVE-2026-35166?

Upgrade github.com/gohugoio/hugo to 0.159.2 or later.

## Is CVE-2026-35166 being exploited?

There is no known exploitation of CVE-2026-35166 in the wild and no public exploit code.

## Other vulnerabilities in gohugoio hugo

- [CVE-2026-75926](https://insights.sbomify.com/CVE-2026-75926/): Hugo 0.162.0 to 0.164.x - Node Permission Model Bypass via Default TailwindCSS Child-Process Grant (critical 9.3)
- [CVE-2026-100690](https://insights.sbomify.com/CVE-2026-100690/): Hugo v0.161.0 to v0.165.0 Arbitrary File Read via Symlinks (high 8.7)
- [CVE-2026-100692](https://insights.sbomify.com/CVE-2026-100692/): Hugo before v0.166.0 Path Traversal via Symlinked Mount Roots (high 8.7)
- [CVE-2026-100693](https://insights.sbomify.com/CVE-2026-100693/): Hugo v0.162.0 before v0.166.0 IP-literal Deny Rule Bypass (high 8.6)
- [CVE-2020-26284](https://insights.sbomify.com/CVE-2020-26284/): Hugo can execute a binary from the current directory on Windows (high 7.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35166 and fix it if it is affected.

What it is: CVE-2026-35166 is a medium-severity cross-site scripting vulnerability in gohugoio hugo, published on 6 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-35166 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/gohugoio/hugo (Go): affected from 0.60.0; fixed in 0.159.2
- github.com/gohugoio/hugo (Go): affected from 0.60.0; fixed in 0.159.2
- github.com/gohugoio/hugo (Go): affected from 0.60.0; fixed in 0.159.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-35166/ (Markdown: https://insights.sbomify.com/CVE-2026-35166/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35166
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35166
- OSV: https://osv.dev/vulnerability/CVE-2026-35166

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35166/
Summaries are generated and may contain mistakes; the official description above is the record.