Server-Side Request Forgery Vulnerability in Dendrite by Element
CVE-2026-63096

6.9MEDIUM

Key Information:

Vendor

Matrix-org

Status
Dendrite
Vendor
CVE Published:
17 July 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-63096?

Dendrite, up to version 0.13.8, is vulnerable to a server-side request forgery (SSRF) that enables unauthenticated attackers to manipulate the server into establishing outbound TLS connections to arbitrary hosts and ports. This vulnerability arises from the lack of validation on the serverName parameter within the legacy media download endpoint. Attackers can exploit distinguishable error responses and leaked internal IP addresses from error messages, which allows them to perform blind port scanning and enumerate the internal network topology. This poses a significant risk to the integrity and confidentiality of sensitive network information.

Affected Version(s)

dendrite 0 <= 0.13.8

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-63096 - Proof of Concept

References

https://github.com/geo-chen/oss/blob/main/dendrite.md#fin...
technical-descriptionexploit
https://www.vulncheck.com/advisories/dendrite-ssrf-via-un...
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

George Chen
.