CVE-2026-109597: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in gohugoio hugo
Description
Hugo versions from 0.60.0 up to but not including 0.167.0 contain a stored cross-site scripting (XSS) vulnerability. This flaw allows Markdown content authors to inject malicious HTML by crafting explicit heading IDs. The vulnerability arises from improper neutralization of input during web page generation, specifically in the unescaped href attribute in .TableOfContents or .Fragments.ToHTML output. This can enable attackers to inject elements with event handlers into rendered pages, potentially leading to client-side code execution.
CVSS v4.0
Score 5.1medium
Affected software
gohugoio
hugo
pkg:golang/github.com/gohugoio/hugoRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-109597 is a stored cross-site scripting vulnerability in the Hugo static site generator affecting versions >=0.60.0 and <0.167.0. The issue occurs because Markdown content authors can supply crafted explicit heading IDs that break out of the unescaped href attribute in .TableOfContents or .Fragments.ToHTML output. This improper input neutralization allows injection of HTML elements with event handlers into the generated pages, leading to potential XSS attacks.
Potential Impact
Successful exploitation allows an attacker with the ability to author Markdown content to inject malicious HTML and JavaScript into generated pages. This can lead to client-side code execution in users' browsers viewing the affected pages. The vulnerability requires author-level privileges and user interaction (UI:P) but does not require elevated privileges or user credentials.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid using untrusted Markdown content with explicit heading IDs or sanitize inputs before rendering. Monitor the vendor's announcements for updates and patches addressing this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-10-12T20:59:18.909Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6acd63de2cdf04f656e1e416
Added to database: 10/12/2026, 22:49:02 UTC
Last enriched: 10/12/2026, 23:49:20 UTC
Last updated: 10/13/2026, 01:48:17 UTC
Views: 1
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