The on_get_missing_events function in handlers/federation.py in Matrix Synapse before 0.31.1 has a security bug in the get_missing_events federation API where event visibility rules were not applied correctly.

The remote Ubuntu 18.04 ESM host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-6076-1 advisory.

    It was discovered that Synapse incorrectly handled certain inputs. If a user or an automated system were     tricked into opening a specially crafted input file, a remote attacker could possibly use this issue to     cause a denial of service. (CVE-2019-18835, CVE-2018-12291, CVE-2018-10657)

    It was discovered that Synapse incorrectly handled certain inputs. If a user or an automated system were     tricked into opening a specially crafted input file, a remote attacker could possibly use this issue to     hijack the session. (CVE-2019-11842, CVE-2018-12423)

    It was discovered that Synapse incorrectly handled certain inputs. If a user or an automated system were     tricked into opening a specially crafted input file, a remote attacker could possibly use this issue to     perform

    spoofing or user impersonation. (CVE-2019-5885, CVE-2018-16515)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

This update for matrix-synapse fixes the following security issue :

  - CVE-2018-12291: visibility rules were not applied     correctly in the get_missing_events federation API     (boo#1096833)

Update to latest Synapse release which fixes CVE-2018-12291 (0.31.1) and a second security bug in 0.31.2:
https://github.com/matrix-org/synapse/releases/tag/v0.31.2

This update includes a new package which is a dependency introduced by synapse-0.31

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
175821	Ubuntu 18.04 ESM : Synapse vulnerabilities (USN-6076-1)	Nessus	Ubuntu Local Security Checks	critical
123194	openSUSE Security Update : matrix-synapse (openSUSE-2019-475)	Nessus	SuSE Local Security Checks	high
120512	Fedora 28 : matrix-synapse / python-prometheus_client (2018-6e759af8fb)	Nessus	Fedora Local Security Checks	high
110633	openSUSE Security Update : matrix-synapse (openSUSE-2018-654)	Nessus	SuSE Local Security Checks	high

Detections

Analytics

CVE-2018-12291

high

Tenable Plugins

critical

high

high

high