CVE-2019-5885

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-03-21 · updated 2026-06-17
Weakness: CWE-330

Description

Matrix Synapse before 0.34.0.1, when the macaroon_secret_key authentication parameter is not set, uses a predictable value to derive a secret key and other secrets which could allow remote attackers to impersonate users.

Affected products

Fedoraproject Fedora: 28, 29
matrix-org synapse: before 0.34.0.1 — fixed in 0.34.0.1

How to fix

Upgrade to a fixed version: matrix-org synapse 0.34.0.1. Check the vendor advisory for mitigations.

References

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/32Y6KD3OAHCG5P33HC2QEX3NUZOSXCGZ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VMCLO5PUPBA756UKY72PKUWL4RRM4W6K/
https://matrix.org/blog/2019/01/10/critical-security-update-synapse-0-34-0-1-synapse-0-34-1-1/
https://matrix.org/blog/2019/01/15/further-details-on-critical-security-update-in-synapse-affecting-all-versions-prior-to-0-34-1-cve-2019-5885/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/32Y6KD3OAHCG5P33HC2QEX3NUZOSXCGZ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VMCLO5PUPBA756UKY72PKUWL4RRM4W6K/
https://matrix.org/blog/2019/01/10/critical-security-update-synapse-0-34-0-1-synapse-0-34-1-1/
https://matrix.org/blog/2019/01/15/further-details-on-critical-security-update-in-synapse-affecting-all-versions-prior-to-0-34-1-cve-2019-5885/

Get alerted when CVE-2019-5885 or the next vulnerability affects your stack