Global infos:

Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. MMR makes requests to other servers as part of normal operation, and these resource owners can return large amounts of JSON back to MMR for parsing. In parsing, MMR can consume large amounts of memory and exhaust available memory. This is fixed in MMR v1.3.8. Users are advised to upgrade. For users unable to upgrade; forward proxies can be configured to block requests to unsafe hosts. Alternatively, MMR processes can be configured with memory limits and auto-restart. Running multiple MMR processes concurrently can help ensure a restart does not overly impact users.

CVE Status: Awaiting Analysis

References:

[email protected]

[email protected]

Metrics:

Attribute	Value
Attack Complexity	LOW
Attack Vector	NETWORK
Availability Impact	LOW
Base Score	5.3
Base Severity	MEDIUM
Confidentiality Impact	NONE
Integrity Impact	NONE
Privileges Required	NONE
Scope	UNCHANGED
User Interaction	NONE
Vector String	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploitability Score	3.9
Impact Score	1.4
Source	[email protected]
Type	Secondary

Links:

Exploit-db
Github