# CVE-2026-10618: Hugo 0.93.0 through 0.165.0 Stored Cross-Site Scripting via Unescaped Code-Fence Attribute Values

> Attackers can inject malicious scripts via unescaped code-fence attributes in Hugo, leading to stored XSS for all site visitors.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 24 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-10618, GHSA-2gp4-jcxx-7hpr, MINI-3qmx-px8g-qr6p, MINI-q439-h444-r7fg, UBUNTU-CVE-2026-10618

## What is CVE-2026-10618?

CVE-2026-10618 is a medium-severity cross-site scripting vulnerability in gohugoio hugo, published on 24 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Hugo's default fenced-code-block renderer writes attribute values taken from the code-fence info string into the rendered HTML without escaping them. New in markup/internal/attributes/attributes.go converts every attribute value from a byte slice to a string as it is stored, deliberately dropping the escaping that used to happen there, and RenderAttributes in the same file escapes only values that are still byte slices, so its escaping branch is never reached and every value is written verbatim. The function's documentation states that it performs HTML escaping of string attributes, which it does not. A quote inside an attribute value in the info string therefore terminates the attribute and allows a further attribute, including an event handler, to be placed on the wrapper element, and the script runs for every visitor who loads the page. This path is reached under the default configuration, with code fences enabled and without goldmark's unsafe setting or any custom render hook. Attribute names beginning with on are filtered when the attributes are parsed, so injection is achieved through the value rather than the name.

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

## Which versions are affected by CVE-2026-10618?

It affects 1 product.


Products: Gohugo Hugo.

## How do I fix CVE-2026-10618?

Upgrade to a fixed version.

## Is CVE-2026-10618 being exploited?

There is no known exploitation of CVE-2026-10618 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-2026-10618 and fix it if it is affected.

What it is: CVE-2026-10618 is a medium-severity cross-site scripting vulnerability in gohugoio hugo, published on 24 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-10618 in the wild and no public exploit code.

Affected product: gohugoio hugo. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-10618/ (Markdown: https://insights.sbomify.com/CVE-2026-10618/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10618
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10618
- OSV: https://osv.dev/vulnerability/CVE-2026-10618

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-10618/
Summaries are generated and may contain mistakes; the official description above is the record.