CVE-2026-82285

Bisheng through version 2.6.0-fix2 contains a server-side request forgery flaw in its POST /api/v1/workflow/report/callback endpoint, which requires no authentication and applies no URL scheme restrictions or host filtering. An unauthenticated remote attacker can submit arbitrary URLs, causing the server to issue requests to internal network services or cloud instance metadata endpoints on the attacker's behalf. Captured responses are stored in object storage, and the attacker can retrieve them using caller-supplied object names, enabling exfiltration of internal service data or cloud metadata contents (potentially including instance credentials). Any deployment running an affected bisheng version with the workflow API reachable by untrusted clients is exposed, with cloud-hosted instances most at risk from metadata service abuse. No public proof-of-concept or confirmed in-the-wild exploitation is known; EPSS currently estimates a 0.3% probability of exploitation within 30 days.

What to do: Upgrade bisheng to a release newer than 2.6.0-fix2 as soon as a patched version is available; until then, restrict access to /api/v1/workflow/report/callback at a reverse proxy or firewall (authentication or IP allowlisting) and block outbound requests from the application host to 169.254.169.254 and internal RFC1918 ranges. Review object storage for unexpectedly created objects and server logs for unauthenticated POSTs to the callback endpoint as indicators of probing or exploitation.