CVE-2025-1522
📋 TL;DR
This CVE-2025-1522 vulnerability in PostHog allows authenticated attackers to perform Server-Side Request Forgery (SSRF) through the database_schema method, potentially exposing internal network resources and sensitive information. The flaw exists due to insufficient URI validation before making requests. Only PostHog installations with authenticated user access are vulnerable.
💻 Affected Systems
- PostHog
📦 What is this software?
Posthog by Posthog
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains access to internal services, cloud metadata, or sensitive data through SSRF, potentially leading to lateral movement and full system compromise.
Likely Case
Information disclosure of internal network resources, configuration files, or limited data accessible via HTTP requests from the PostHog server.
If Mitigated
Minimal impact with proper network segmentation, authentication controls, and input validation in place.
🎯 Exploit Status
Authentication required; SSRF exploitation typically straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Commit 3732c0fd9551ed29521b58611bf1e44d918c1032 or later
Vendor Advisory: https://github.com/PostHog/posthog/commit/3732c0fd9551ed29521b58611bf1e44d918c1032
Restart Required: Yes
Instructions:
1. Update PostHog to version containing commit 3732c0fd9551ed29521b58611bf1e44d918c1032. 2. Restart PostHog services. 3. Verify the fix by checking the commit hash.
🔧 Temporary Workarounds
Network Segmentation
linuxRestrict PostHog server's outbound network access to only required services
iptables -A OUTPUT -p tcp --dport 80 -j DROP
iptables -A OUTPUT -p tcp --dport 443 -j DROP
Authentication Hardening
allImplement strict authentication controls and monitor for suspicious database_schema method usage
🧯 If You Can't Patch
- Implement strict network egress filtering to block unauthorized outbound requests from PostHog server
- Enforce least privilege authentication and monitor for unusual database_schema API calls
🔍 How to Verify
Check if Vulnerable:
Check if PostHog version predates commit 3732c0fd9551ed29521b58611bf1e44d918c1032Check Version:
git log --oneline -1Verify Fix Applied:
Confirm current installation includes commit 3732c0fd9551ed29521b58611bf1e44d918c1032 or later📡 Detection & Monitoring
Log Indicators:
- Unusual outbound HTTP requests from PostHog process
- Multiple database_schema API calls with varying parameters
- Requests to internal IP addresses or metadata endpoints
Network Indicators:
- Unexpected outbound HTTP traffic from PostHog server to internal networks
- Requests to cloud metadata services (169.254.169.254, etc.)
SIEM Query:
source="posthog" AND (uri="*database_schema*" OR method="POST" AND path="/api/database_schema")