Bug 1901508 (CVE-2020-26890)

Summary:	CVE-2020-26890 matrix-synapse: DoS attack due to invalid JSON
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	djc
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
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Clone Of:		Environment:
Last Closed:	2020-11-25 17:33:57 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1901509
Bug Blocks:

Description Guilherme de Almeida Suckevicz 2020-11-25 13:16:06 UTC

Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of m.room.member events, allowing remote attackers to execute a denial of service attack against the federation and common Matrix clients. If such a malformed event is accepted into the room's state, the impact is long-lasting and is not fixed by an upgrade to a newer version, requiring the event to be manually redacted instead. Since events are replicated to servers of other room members, the impact is not constrained to the server of the event sender.

Reference:
https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f

Comment 1 Guilherme de Almeida Suckevicz 2020-11-25 13:16:23 UTC

Created matrix-synapse tracking bugs for this issue:

Affects: fedora-all [bug 1901509]

Comment 2 Product Security DevOps Team 2020-11-25 17:33:57 UTC

This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.