CVE-2026-66921 Pivotick - Stored DOM-Based Cross-Site Scripting via Unescaped Markdown Node References
Attackers can execute arbitrary JavaScript in victims' browsers via unescaped Markdown node references, potentially accessing session data or modifying content.
- 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
- None listed
What is CVE-2026-66921?
CVE-2026-66921 is a medium-severity cross-site scripting vulnerability in pivotick, published on 28 Jul 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
Pivotick’s Markdown node-reference renderer failed to HTML-escape the attacker-controlled nodeName value before interpolating it into both the data-node-name attribute and the body of a generated <span> element.
Because the node-reference tokenizer rejected only square brackets, a crafted node name could still contain quotation marks, angle brackets, or other HTML metacharacters. An attacker could therefore terminate the quoted attribute or inject additional HTML elements and event-handler attributes.
When malicious node-reference content is rendered by a consumer that does not apply DOMPurify or equivalent sanitization, arbitrary JavaScript may execute in the victim’s browser in the security context of the application. Successful exploitation requires a victim to open or render a crafted graph or note and could allow the attacker to access same-origin information, modify displayed content, or perform actions using the victim’s session.
The patch resolves the issue by applying context-appropriate HTML escaping to node names before inserting them into either HTML text or quoted attribute values. The shared escaping function now encodes ampersands, angle brackets, and both types of quotation marks.
Weakness: CWE-79
Which versions are affected by CVE-2026-66921?
How do I fix CVE-2026-66921?
No fix has been published for CVE-2026-66921 yet. Limit exposure of the affected software until one is available.
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-2026-66921 being exploited?
There is no known exploitation of CVE-2026-66921 in the wild and no public exploit code.
Sources
Also known as GHSA-vx7v-g6x3-qh2m.