CVE-2026-63096 — Dendrite 0.13.8 SSRF via Unauthenticated Legacy Media Download Endpoint

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.

Published Jul 17, 2026Updated Jul 28, 2026Sources: cvelistV5, VulnCheck

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

chance of exploitation in 30 days

Affects

matrix org

dendrite

CVSS base

5.8

MEDIUM

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

PoC

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

matrix org

Products (1)

dendrite

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
5.8	CVSS 3.1	MEDIUM	—	—	cvelistV5

Weakness & attack patterns

CWE-918

References

2 on the record

github.com/geo-chen/oss/blob/main/dendrite.md#finding-2-unauthenticated-ssrf-and-internal-port-scanner-via-legacy-_matrixmediar0download
technical-description, exploit
www.vulncheck.com/advisories/dendrite-ssrf-via-unauthenticated-legacy-media-download-endpoint
third-party-advisory

Elsewhere on this site

matrix orgevery CVE for this vendor
CWE-918other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.