CVE-2020-26890

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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.

Matrix Synapse versiones anteriores a 1.20.0, permite erróneamente valores de JSON NaN, Infinity e -Infinity no estándar en campos de eventos m.room.member, permitiendo a atacantes remotos ejecutar un ataque de denegación de servicio contra la federación y unos clientes comunes de Matrix. Si un evento malformado es aceptado en el estado de la sala, el impacto es duradero y no es corregido con una actualización a una versión más nueva, requiriendo que el evento sea redactado manualmente. Dado que los eventos son replicados en los servidores de otros miembros de la sala, el impacto no está limitado al servidor del remitente del evento

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-10-08 CVE Reserved
2020-11-24 CVE Published
2024-08-04 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-20: Improper Input Validation

CAPEC

References (3)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Matrix Search vendor "Matrix"		Synapse Search vendor "Matrix" for product "Synapse"				< 1.20.0 Search vendor "Matrix" for product "Synapse" and version " < 1.20.0"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				32 Search vendor "Fedoraproject" for product "Fedora" and version "32"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				33 Search vendor "Fedoraproject" for product "Fedora" and version "33"		-		Affected