Cyber Resilience

CVE-2024-31208

MediumDDoS

Published: 23 April 2024

Published
23 April 2024
Modified
26 August 2025
KEV Added
Patch
CVSS Score v3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0419 89.0th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2024-31208 is a medium-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Fedoraproject Fedora. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application Exhaustion Flood (T1499.003); ranked in the top 11.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Synapse is an open-source Matrix homeserver. A remote Matrix user with malicious intent, sharing a room with Synapse instances before 1.105.1, can dispatch specially crafted events to exploit a weakness in the V2 state resolution algorithm. This can induce high…

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CPU consumption and accumulate excessive data in the database of such instances, resulting in a denial of service. Servers in private federations, or those that do not federate, are not affected. Server administrators should upgrade to 1.105.1 or later. Some workarounds are available. One can ban the malicious users or ACL block servers from the rooms and/or leave the room and purge the room using the admin API.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

Vulnerability allows remote room-sharing attackers to send crafted events exploiting Synapse V2 state resolution, causing application-level CPU exhaustion and database bloat for DoS.

Affected Assets

matrix
synapse
≤ 1.105.1
fedoraproject
fedora
38, 39, 40

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-770

This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.

addresses: CWE-770

Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.

addresses: CWE-770

Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.

addresses: CWE-770

Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.

addresses: CWE-770

Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.

addresses: CWE-770

Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.

addresses: CWE-770

Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.

addresses: CWE-770

Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.

References