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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | matrix-synapse | 0.24.0+dfsg-1ubuntu0.1~esm1 | USN-6076-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | matrix-sydent | < 1.0.3 | 1.0.3 | GHSA-gwf7-vfjf-wf6x |
| PyPI | matrix-synapse | < 0.99.3.1 | 0.99.3.1 | GHSA-gwf7-vfjf-wf6x |
Advisories 1
- USN-6076-1 matrix-synapse vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026