CVE-2026-45076
Description
A flaw was found in Synapse, an open source Matrix homeserver implementation. A remote attacker, specifically a malicious homeserver, can craft room events in federated rooms to prevent Synapse from providing full history to paginating clients. This leads to a denial of service, where clients fail to display room history.
Statement
Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other); Reduce Performance
This issue can make the product perform more slowly. If an attacker can influence the number of iterations in the loop, then this performance problem might allow a denial of service by consuming more platform resources than intended.
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