CVE-2026-63096

MEDIUM 5.8

Dendrite 0.13.8 SSRF via Unauthenticated Legacy Media Download Endpoint

CVSS Score

5.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-918
Vendor	matrix-org
Product	dendrite
Published	Jul 17, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

None

Availability

None

Affected Versions

matrix-org / dendrite

0 ≤ 0.13.8

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/geo-chen/oss/blob/main/dendrite.md#finding-2-unauthenticated-ssrf-and-internal-port-scanner-via-legacy-_matrixmediar0download vulncheck.com: https://www.vulncheck.com/advisories/dendrite-ssrf-via-unauthenticated-legacy-media-download-endpoint

Credits

George Chen