CVE-2024-37302: element-hq synapse

Vulnerability summary

CVE-2024-37302 is a high (CVSS 7.5) vulnerability in element-hq synapse. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 47.4% of scored vulnerabilities.

Timeline

1. 03-12-2024
   PublishedVulnerability first disclosed.
2. 03-12-2024
   Last modifiedVulnerability information updated.

Description

Synapse is an open-source Matrix homeserver. Synapse versions before 1.106 are vulnerable to a disk fill attack, where an unauthenticated adversary can induce Synapse to download and cache large amounts of remote media. The default rate limit strategy is insufficient to mitigate this. This can lead to a denial of service, ranging from further media uploads/downloads failing to completely unavailability of the Synapse process, depending on how Synapse was deployed. Synapse 1.106 introduces a new "leaky bucket" rate limit on remote media downloads to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data to be cached.

• CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.