Authenticated PostHog users vulnerable to SSRF

Vulnerability Description

PostHog provides open-source product analytics, session recording, feature flagging and A/B testing that you can self-host. A server-side request forgery (SSRF), which can only be exploited by authenticated users, was found in Posthog. Posthog did not verify whether a URL was local when enabling webhooks, allowing authenticated users to forge a POST request. This vulnerability has been addressed in `22bd5942` and will be included in subsequent releases. There are no known workarounds for this vulnerability.

References

• https://github.com/PostHog/posthog/security/advisories/GHSA-wqqw-r8c5-j67c
• https://github.com/PostHog/posthog/commit/22bd5942638d5d9bc4bd603a9bfe8f8a95572292
• https://securitylab.github.com/advisories/GHSL-2023-185_posthog_posthog/