Comfyui EUVD-2026-23737

Exploitation requires: (1) Valid authentication to the ComfyUI instance (PR:L); (2) Ability to submit data to the getuserdata endpoint or user profile modification endpoint (no special configuration needed for standard deployments); (3) Another user must view the attacker's injected data or click a link containing the malicious payload (UI:R). The vulnerability is NOT exploitable against default configurations without a login credential. Exploitation is limited to the user's current security context (S:U) - XSS payload cannot escalate privileges or access other users' data directly but can steal session cookies or perform actions as the victim.

CVSS 3.5 (Low) with EPSS data unavailable suggests limited real-world risk despite public exploit availability. The Low CVSS reflects mandatory constraints: PR:L (login required), UI:R (user interaction required), and S:U (scope unchanged-impact limited to same security context). CVSS vector shows AC:L (low complexity) and AV:N (network-accessible), making exploitation straightforward once authenticated, but the authentication and interaction barriers significantly reduce attack surface. Public exploit availability (POC confirmed) increases concern for targeted attacks against ComfyUI instances, but absence from CISA KEV indicates no confirmed active exploitation in the wild at analysis time. Risk is elevated in multi-user ComfyUI deployments where an attacker with login access could inject payloads affecting other users, particularly if the instance is exposed to untrusted networks. For single-user local installations, risk is minimal. E:P (exploit code mature/proof-of-concept exists) and RL:X (vendor has not issued a patch) compound the remediation burden.

An authenticated attacker logs into a ComfyUI instance and injects malicious JavaScript into a user profile field (e.g., username, email, or preferences) via the userdata endpoint. When another user or an administrator views the attacker's profile or user list, the injected script executes in their browser with their session privileges, allowing session hijacking, credential theft, or further system compromise. The publicly available exploit (gist.github.com/YLChen-007/50f0cdc5e3f7b737ce99c783e487ca0d) provides proof-of-concept payloads.