from https://github.com/matrix-org/synapse/releases/tag/v0.31.1

Changes in synapse v0.31.1 (2018-06-08)

v0.31.1 fixes a security bug in the get_missing_events federation API
where event visibility rules were not applied correctly.

We are not aware of it being actively exploited but please upgrade asap.

Bug Fixes:

    Fix event filtering in get_missing_events handler (PR #3371)

https://github.com/matrix-org/synapse/commit/ad9edd1d968f19dd4d7c65102fe552076ca9bc5a

Bug ID	1096833
Summary	VUL-0: matrix-synapse: event visibility rules not applied correctly
Classification	openSUSE
Product	openSUSE Distribution
Version	Leap 15.0
Hardware	Other
OS	Other
Status	NEW
Severity	Normal
Priority	P5 - None
Component	Security
Assignee	okurz@suse.com
Reporter	astieger@suse.com
QA Contact	security-team@suse.de
Found By	---
Blocker	---