What’s Vulnerable › Vulnerabilities

CVE-2018-10657

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-05-02 · updated 2026-06-17
• Weakness: CWE-20

Description

Matrix Synapse before 0.28.1 is prone to a denial of service flaw where malicious events injected with depth = 2^63 - 1 render rooms unusable, related to federation/federation_base.py and handlers/message.py, as exploited in the wild in April 2018.

Affected products

• matrix-org synapse: before 0.28.1 — fixed in 0.28.1

How to fix

Upgrade to a fixed version: matrix-org synapse 0.28.1. Check the vendor advisory for mitigations.

References

• https://github.com/matrix-org/synapse/commit/33f469ba19586bbafa0cf2c7d7c35463bdab87eb
• https://matrix.org/blog/2018/05/01/security-update-synapse-0-28-1/
• https://github.com/matrix-org/synapse/commit/33f469ba19586bbafa0cf2c7d7c35463bdab87eb
• https://matrix.org/blog/2018/05/01/security-update-synapse-0-28-1/

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