TI-2026-45046 Aliases CVE-2026-63096 GHSA-jrcq-4ccj-6fr8

Dendrite 0.13.8 SSRF via Unauthenticated Legacy Media Download Endpoint

HIGH 70CWE-918Published 2026-07-17 · Updated 2026-07-28

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: —
Confidentiality · integrity · availability: None · None · None
Fix status: No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00335 27th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by the CNA

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
matrix-org	dendrite	up to 0.13.8	—	No fix listed	CNA

dendrite Vendormatrix-org Affected up to 0.13.8 Fixed in — No fix listed CNA

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2026-63096
2026-10-03 Alias added: GHSA-jrcq-4ccj-6fr8

References

Exploit 1

Researcher Disclosure

TI-2023-20035 Sydent does not verify email server certificates CVSS 3.1CRITICAL 9.3
TI-2026-45045 Dendrite 0.13.8 Improper Authorization via POST account/3pid/delete Endpoint CVSS 4.0HIGH 7.1
TI-2026-45047 Dendrite 0.13.8 syncapi /context Endpoint Post-Leave State Exposure CVSS 4.0MEDIUM 5.3
TI-2023-15617 Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites CVSS 3.1MEDIUM 5.0
TI-2023-20039 matrix-appservice-irc IRC command injection via admin commands containing newlines CVSS 3.1CRITICAL 9.8
TI-2021-13807 Matrix libolm before 3.2.3 allows a malicious Matrix homeserver to crash a client (while… CVSS 3.1CRITICAL 9.8

See all 115 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences