# CVE-2026-5160: goldmark vulnerable to Cross-site Scripting (XSS)

> An attacker can execute arbitrary scripts by bypassing URL validation in the goldmark HTML renderer, affecting applications using this Go library.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/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:** 15 Apr 2026
- **Updated:** 15 Apr 2026
- **Also known as:** AZL-83048, AZL-83060, BELL-CVE-2026-5160, CLEANSTART-2026-QG09964, DEBIAN-CVE-2026-5160, GHSA-c97m-vxhj-p7j6, GO-2026-5320, MINI-2376-5fmm-pr7g, MINI-3fhq-f3q9-456q, MINI-5686-gjr7-pqg2, MINI-5767-h34w-c9ph, MINI-62j8-5c44-g8rj, MINI-7jm8-9258-2xjx, MINI-887v-j6w5-q6ph, MINI-985v-3x7g-p93f, MINI-9ffc-q9c8-gr2r, MINI-r6rv-q8vr-g5mv, MINI-v9c9-rpfh-67q7, MINI-vrmg-3hjr-rh82, MINI-x2w5-6698-wmcc, MINI-x8rj-77fm-wxj6, UBUNTU-CVE-2026-5160

## What is CVE-2026-5160?

CVE-2026-5160 is a medium-severity cross-site scripting vulnerability in github.com/yuin/goldmark/renderer/html, published on 15 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

Versions of the package github.com/yuin/goldmark/renderer/html before 1.7.17 are vulnerable to Cross-site Scripting (XSS) due to improper ordering of URL validation and normalization. The renderer validates link destinations using a prefix-based check (IsDangerousURL) before resolving HTML entities. This allows an attacker to bypass protocol filtering by encoding dangerous schemes using HTML5 named character references. For example, a payload such as javascript:alert(1) is not recognized as dangerous during validation, leading to arbitrary script execution in the context of applications that render the URL.

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

## Which versions are affected by CVE-2026-5160?

3 open source packages ship an affected version, including github.com/yuin/goldmark/renderer/html and github.com/yuin/goldmark. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/yuin/goldmark/renderer/html` | Go | All versions | 1.7.17 |
| `github.com/yuin/goldmark/renderer/html` | Go | All versions | 1.7.17 |
| `github.com/yuin/goldmark` | Go | All versions | 1.7.17 |

Products: Yuin Goldmark.

## How do I fix CVE-2026-5160?

Upgrade github.com/yuin/goldmark/renderer/html to 1.7.17 or later.

## Is CVE-2026-5160 being exploited?

There is no known exploitation of CVE-2026-5160 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5160 and fix it if it is affected.

What it is: CVE-2026-5160 is a medium-severity cross-site scripting vulnerability in github.com/yuin/goldmark/renderer/html, published on 15 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-2026-5160 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/yuin/goldmark/renderer/html (Go): affected all versions; fixed in 1.7.17
- github.com/yuin/goldmark/renderer/html (Go): affected all versions; fixed in 1.7.17
- github.com/yuin/goldmark (Go): affected all versions; fixed in 1.7.17

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-2026-5160/ (Markdown: https://insights.sbomify.com/CVE-2026-5160/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5160
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5160
- OSV: https://osv.dev/vulnerability/CVE-2026-5160

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5160/
Summaries are generated and may contain mistakes; the official description above is the record.