matrix-org dendrite up to 0.13.8 Legacy Media Download Endpoint servername server-side request forgery

Summaryinfo

A vulnerability categorized as problematic has been discovered in matrix-org dendrite up to 0.13.8. Affected by this issue is some unknown functionality of the component Legacy Media Download Endpoint. The manipulation of the argument servername results in server-side request forgery. This vulnerability only affects products that are no longer supported by the maintainer. This vulnerability is reported as CVE-2026-63096. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in matrix-org dendrite up to 0.13.8. It has been classified as problematic. Affected is an unknown functionality of the component Legacy Media Download Endpoint. The manipulation of the argument servername with an unknown input leads to a server-side request forgery vulnerability. CWE is classifying the issue as CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. This is going to have an impact on confidentiality. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-63096 since 07/15/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 07/17/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• matrix-org

Name

• dendrite

Version

• 0.13.0
• 0.13.1
• 0.13.2
• 0.13.3
• 0.13.4
• 0.13.5
• 0.13.6
• 0.13.7
• 0.13.8

Support

• end of life

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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