SUMMARY
We have identified and verified an SSRF vulnerability where webhook URLs are not validated, allowing repository administrators to create webhooks targeting internal services, private networks, and cloud metadata endpoints.
AFFECTED COMPONENTS (VERIFIED)
IMPACT
This vulnerability allows repository administrators to perform SSRF attacks, potentially enabling:
a) Cloud Metadata Theft - Access AWS/Azure/GCP credentials via 169.254.169.254 b) Internal Network Access - Target localhost and private networks (10.x, 192.168.x, 172.16.x) c) Port Scanning - Enumerate internal services via response codes and timing d) Data Exfiltration - Full HTTP responses stored in webhook delivery logs e) Internal API Access - Call internal admin panels and Kubernetes endpoints
PROOF OF CONCEPT
Simple example demonstrating localhost access:
ssh localhost webhook create my-repo http://127.0.0.1:8080/internal \
--events push --active
then push to trigger.
{
"cwe_ids": [
"CWE-918"
],
"github_reviewed_at": "2025-11-10T21:34:44Z",
"github_reviewed": true,
"nvd_published_at": null,
"severity": "CRITICAL"
}