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.
- 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-2026-10618?
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
Which versions are affected by CVE-2026-10618?
It affects 1 product.
Products include Gohugo Hugo.
How do I fix CVE-2026-10618?
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-2026-10618 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 Hugo 0.162.0 to 0.164.x - Node Permission Model Bypass via Default TailwindCSS Child-Process Grant
- CVE-2026-100690 Hugo v0.161.0 to v0.165.0 Arbitrary File Read via Symlinks
- CVE-2026-100692 Hugo before v0.166.0 Path Traversal via Symlinked Mount Roots
- CVE-2026-100693 Hugo v0.162.0 before v0.166.0 IP-literal Deny Rule Bypass
- CVE-2020-26284 Hugo can execute a binary from the current directory on Windows
Sources
Also known as DEBIAN-CVE-2026-10618, GHSA-2gp4-jcxx-7hpr, MINI-3qmx-px8g-qr6p, MINI-q439-h444-r7fg, UBUNTU-CVE-2026-10618.