Stigmem before 0.9.0a11 fails to validate the deliveryaddress parameter when creating webhook subscriptions, allowing authenticated users to specify internal loopback and private network destinations. Attackers can trigger matching fact-change events to cause the Stigmem server to issue server-side HTTP POST requests to internal services, enabling blind SSRF attacks against localhost and private network endpoints.

stigmem versions before 0.9.0a12 contain a broken object level authorization vulnerability in the decay sweep endpoint that allows authenticated attackers with write credentials for one tenant to execute decay operations affecting all tenants. Attackers can submit POST requests to the decay sweep endpoint with ttlseconds=0 to expire facts across all tenants, or use dryrun to obtain cross-tenant fact counts and existence information.

stigmem versions before 0.9.0a2 allow unauthenticated access when authentication is disabled on non-loopback deployments. Attackers can perform read, write, and federation operations with anonymous identity when nodes are exposed outside local development environments.