SSRF in Matrix-Org Dendrite
CVE-2026-63096
Dendrite through 0.13.8 contains a server-side request forgery vulnerability that allows unauthenticated attackers to cause the server to open outbound TLS connections to arbitrary hosts and ports by supplying an unvalidated serverName parameter to the legacy media download endpoint. Attackers can exploit distinguishable error response classes and leaked internal IP addresses in error messages to perform blind port scanning and enumerate internal network topology.
Vulnerability class: SSRF (Server-Side Request Forgery)
EPSS: 0.003 (26.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N.
Affected products
- Matrix-org Dendrite — versions 0
Weakness classification (CWE)
References
- Researcher Disclosure (technical-description, exploit)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-63096?
- CVE-2026-63096 is a medium-severity vulnerability in Matrix-Org Dendrite, classified under Server-Side Request Forgery (SSRF). CVSS score: 5.8/10. Published 2026-07-17.
- How severe is CVE-2026-63096?
- Medium severity. CVSS v3 base score is 5.8 out of 10.