CVE-2019-11842

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.

Published: 2019-05-09 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-11842 is rated Moderate Risk (57.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.78%). EPSS rose +1.37% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2019-11842

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.41% 1.78% +1.37%
2 2026-05-20 0.51% 0.41% -0.10%
3 2026-05-18 — 0.51% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-11842

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2019-11842

GitHub Security Advisory for CVE-2019-11842

GHSA-gwf7-vfjf-wf6x · Severity: high · Ecosystem: pip — matrix-sydent and matrix-synapse Use Cryptographically Weak PRNG

OS Trackers for CVE-2019-11842

vendor priority summary link
debian not yet assigned CVE-2019-11842 not yet assigned priority: Debian including 1 source packages (matrix-synapse), 2 status rows across 2 suites (forky, sid): resolved 2. https://security-tracker.debian.org/tracker/CVE-2019-11842
ubuntu medium CVE-2019-11842 medium priority: Ubuntu including 1 source packages (matrix-synapse), 14 status rows across 14 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, trusty, upstream, xenial): not-affected 8, DNE 2, ignored 2, released 2. https://ubuntu.com/security/CVE-2019-11842

Affected software / configurations for CVE-2019-11842

Vendor Product Version Raw CPE
matrix sydent < 1.0.3 cpe:2.3:a:matrix:sydent:*:*:*:*:*:*:*:*
matrix synapse < 0.99.3.1 cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*

References for CVE-2019-11842

cvelogic Threat Intelligence