CVE-2026-109597 Hugo v0.60.0 before v0.167.0 Stored XSS via Table of Contents Heading IDs
Markdown authors can inject malicious HTML via crafted heading IDs in Hugo's Table of Contents, leading to stored XSS on rendered pages.
- 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
What is CVE-2026-109597?
CVE-2026-109597 is a medium-severity cross-site scripting vulnerability in gohugoio hugo, published on 12 Oct 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 from v0.60.0 before v0.167.0 contains a stored cross-site scripting vulnerability that allows Markdown content authors to inject HTML by supplying crafted explicit heading IDs. Attackers can break out of the unescaped href attribute in .TableOfContents or .Fragments.ToHTML output to inject elements with event handlers into rendered pages.
Weakness: CWE-79
Which versions are affected by CVE-2026-109597?
How do I fix CVE-2026-109597?
Upgrade to a fixed version.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-109597 being exploited?
There is no known exploitation of CVE-2026-109597 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-109597, GHSA-hh58-7hgh-xf3r, GHSA-wcpj-vcvm-j4pg, MINI-f2w5-wg5p-5wm3, MINI-v3gj-8f92-2f35, UBUNTU-CVE-2026-109597.