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CVE-2026-63096

Dendrite 0.13.8 SSRF via Unauthenticated Legacy Media Download Endpoint

Published: Jul 17, 2026Updated: Jul 17, 2026 Sources: CVE List NVDCWE-918
5.8MEDIUM
NVD MITRE
EPSS Score
0.2%
Top 88.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:CC:LI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:LConfidentiality
Low
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-918

Affected Products

matrix-org
oss-project·DEaka matrix-js-sdk, matrix appservice irc, synapse
dendriteOn-prem
Communications / messaging-chat

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Command and Control
Initial Access
View detailed technique mapping

References

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

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