gohugoio Hugo up to 0.165.0 Fenced-Code-Block Renderer attributes.go RenderAttributes cross site scripting

Summaryinfo

A vulnerability classified as problematic was found in gohugoio Hugo up to 0.165.0. This issue affects the function RenderAttributes of the file markup/internal/attributes/attributes.go of the component Fenced-Code-Block Renderer. Executing a manipulation can lead to cross site scripting. This vulnerability appears as CVE-2026-10618. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability has been found in gohugoio Hugo up to 0.165.0 and classified as problematic. This vulnerability affects the function RenderAttributes of the file markup/internal/attributes/attributes.go of the component Fenced-Code-Block Renderer. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-10618 since 06/02/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1059.007 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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Vendor

• gohugoio

Name

• Hugo

Version

• 0.165

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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