CVE-2019-11842 json
matrix-sydent and matrix-synapse Use Cryptographically Weak PRNG
published 2019-05-09 7 y ago modified 2026-07-13 3 mo ago also GHSA-gwf7-vfjf-wf6x , PYSEC-2019-185 , PYSEC-2026-2620 , EUVD-2019-0082
- cvss
- 7.5
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.8%
- EPSS 1.8% chance of exploitation in 30 days, percentile 78%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi matrix-sydent 1.0.3
- pypi matrix-synapse 0.99.3.1
- matrix sydent 1.0.3
- matrix synapse 0.99.3.1
- matrix-synapse Ubuntu Pro 18.04 LTS 0.24.0+dfsg-1ubuntu0.1~esm1
ubuntu advisories UBUNTU-CVE-2019-11842
Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
Exploit prediction
1.80% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:P/I:N/A:N |
| GitHub | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| OSV | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | matrix-sydent | <1.0.3 |
1.0.3 |
| pypi | matrix-synapse | <0.99.3.1 |
0.99.3.1 |
Classification
- Weakness
-
- CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
References
-
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/
vendor-advisory, article
-
nvd.nist.gov
/vuln/detail/CVE-2019-11842
advisory
-
github.com
/advisories/GHSA-gwf7-vfjf-wf6x
advisory
-
github.com
/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2019-185.yaml
web
-
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
web
-
pypi.org
/project/matrix-sydent
package
Sources
- CVE List CVE-2019-11842
- GitHub Advisory GHSA-gwf7-vfjf-wf6x
- NVD CVE-2019-11842
- OSV PYSEC-2019-185
- OSV PYSEC-2026-2620
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.