---
id: CVE-2019-11842
aliases:
  - GHSA-gwf7-vfjf-wf6x
  - PYSEC-2019-185
  - PYSEC-2026-2620
title: matrix-sydent and matrix-synapse Use Cryptographically Weak PRNG
summary: matrix-sydent and matrix-synapse Use Cryptographically Weak PRNG
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
vendor: matrix-sydent
product: matrix-sydent
ecosystem: pip
affected:
  - matrix-sydent < 1.0.3
  - matrix-synapse < 0.99.3.1
patched:
  - matrix-sydent 1.0.3
  - matrix-synapse 0.99.3.1
published: '2022-05-24'
updated: '2026-07-13'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-gwf7-vfjf-wf6x'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2019-11842'
  - url: 'https://github.com/advisories/GHSA-gwf7-vfjf-wf6x'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2019-185.yaml
  - url: >-
      https://matrix.org/blog/2019/05/03/security-updates-sydent-1-0-3-synapse-0-99-3-1-and-riot-android-0-9-0-0-8-99-0-8-28-a
tags:
  - osv
  - pip
epss: 0.01795
epssPercentile: 0.77498
ingestedAt: '2026-07-13T18:57:58.650Z'
---

## Overview

An issue was discovered in Matrix Sydent before 1.0.3 and Synapse before 0.99.3.1. Random number generation is mishandled, which makes it easier for attackers to predict a Sydent authentication token or a Synapse random ID.

## Affected packages

- `matrix-sydent < 1.0.3`
- `matrix-synapse < 0.99.3.1`

## Remediation

Upgrade to a patched release:

- `matrix-sydent 1.0.3`
- `matrix-synapse 0.99.3.1`