CVE-2025-51859 Cross-site scripting in n/a
Attackers can execute arbitrary scripts in users' browsers via malicious AI agent prompts, leading to session token theft and account hijacking.
- 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-2025-51859?
CVE-2025-51859 is a medium-severity cross-site scripting vulnerability in n/a, published on 22 Jul 2025. 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
Stored Cross-Site Scripting (XSS) vulnerability in Chaindesk thru 2025-05-26 in its agent chat component. An attacker can achieve arbitrary client-side script execution by crafting an AI agent whose system prompt instructs the underlying Large Language Model (LLM) to embed malicious script payloads (e.g., SVG-based XSS) into its chat responses. When a user interacts with such a malicious agent or accesses a direct link to a conversation containing an XSS payload, the script executes in the user's browser. Successful exploitation can lead to the theft of sensitive information, such as JWT session tokens, potentially resulting in account hijacking.
Weakness: CWE-79
Which versions are affected by CVE-2025-51859?
How do I fix CVE-2025-51859?
No fix has been published for CVE-2025-51859 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-2025-51859 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-51859 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-cv56-r9m6-79rx.