CVE-2020-26257

Denial of service attack via incorrect parameters to federation APIs

Published Dec 9, 2020 CVSS 3.1 · 6.5 Medium EPSS 2.4% KEV · Not listed
Description
Matrix is an ecosystem for open federated Instant Messaging and VoIP. Synapse is a reference "homeserver" implementation of Matrix. A malicious or poorly-implemented homeserver can inject malformed events into a room by specifying a different room id in the path of a `/send_join`, `/send_leave`, `/invite` or `/exchange_third_party_invite` request. This can lead to a denial of service in which future events will not be correctly sent to other servers over federation. This affects any server which accepts federation requests from untrusted servers. The Matrix Synapse reference implementation before version 1.23.1 the implementation is vulnerable to this injection attack. Issue is fixed in version 1.23.1. As a workaround homeserver administrators could limit access to the federation API to trusted servers (for example via `federation_domain_whitelist`).

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2020-0106 Matrix is an ecosystem for open federated Instant Messaging and VoIP. Synapse is a reference \"homeserver\" implementation of Matrix. A malicious or poorly-implemented homeserver can inject malformed events into a room by specifying a different room id in the path of a `/send_join`, `/send_leave`, `/invite` or `/exchange_third_party_invite` request. This can lead to a denial of service in which future events will not be correctly sent to other servers over federation. This affects any server which accepts federation requests from untrusted servers. The Matrix Synapse reference implementation before version 1.23.1 the implementation is vulnerable to this injection attack. Issue is fixed in version 1.23.1. As a workaround homeserver administrators could limit access to the federation API to trusted servers (for example via `federation_domain_whitelist`).
Github GHSA Github GHSA GHSA-hxmp-pqch-c8mm Denial of service attack via incorrect parameters in Matrix Synapse
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 4, 2024, 3:56 PM
Reserved
Oct 1, 2020, 12:00 AM
Status
Modified
Published
Dec 9, 2020, 7:15 PM
Modified
Jun 17, 2026, 3:07 AM