Description
Graylog through 7.1.4 validates outbound URLs against an allowlist before making requests but fails to re-validate after following HTTP redirects. Attackers with lookup table or event notification permissions can craft allowlisted endpoints that redirect to internal services, enabling the server to fetch and return internal responses.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Graylog2 | graylog2-server | ≤ 7.1.4 | — |
Advisories 1
- WID-SEC-2026-3421 Graylog: Schwachstelle ermöglicht Offenlegung von Informationen BSI CERT-Bund (WID) · Sep 16, 2026
References
- GitHub Issue #26591 issue-tracking
- https://github.com/Graylog2/graylog2-server product
- the allowlist is checked only against the pre-redirect URL technical-description
- VulnCheck Advisory: Graylog through 7.1.4 Server-Side Request Forgery via HTTP Redirect third-party-advisory