CVE-2021-39161

Cross-site scripting via category name in Discourse

Severity Score

5.4

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Discourse is an open source platform for community discussion. In affected versions category names can be used for Cross-site scripting(XSS) attacks. This is mitigated by Discourse's default Content Security Policy and this vulnerability only affects sites which have modified or disabled or changed Discourse's default Content Security Policy have allowed for moderators to modify categories. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. Users are advised to ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.

Discourse es una plataforma de código abierto para el debate comunitario. En las versiones afectadas los nombres de las categorías pueden ser usados para ataques de tipo Cross-site scripting (XSS). Esto es mitigado por la Política de Seguridad de Contenidos por predeterminada de Discourse y esta vulnerabilidad sólo afecta a los sitios que han modificado o deshabilitado o cambiado la Política de Seguridad de Contenidos predeterminada de Discourse han permitido a los moderadores modificar las categorías. Este problema está parcheado en las últimas versiones estables, beta y de prueba de Discourse. Se aconseja a usuarios que se aseguren de que la Política de Seguridad de Contenidos está habilitada y no ha sido modificada de forma que sea más vulnerable a los ataques de tipo XSS.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

High

Authentication

Single

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-08-16 CVE Reserved
2021-08-26 CVE Published
2023-03-19 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CAPEC

References (1)

URL	Tag	Source
https://github.com/discourse/discourse/security/advisories/GHSA-xhmc-9jwm-wqph	Third Party Advisory

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Discourse Search vendor "Discourse"		Discourse Search vendor "Discourse" for product "Discourse"				< 2.7.8 Search vendor "Discourse" for product "Discourse" and version " < 2.7.8"		-		Affected
Discourse Search vendor "Discourse"		Discourse Search vendor "Discourse" for product "Discourse"				2.8.0 Search vendor "Discourse" for product "Discourse" and version "2.8.0"		beta1		Affected
Discourse Search vendor "Discourse"		Discourse Search vendor "Discourse" for product "Discourse"				2.8.0 Search vendor "Discourse" for product "Discourse" and version "2.8.0"		beta2		Affected
Discourse Search vendor "Discourse"		Discourse Search vendor "Discourse" for product "Discourse"				2.8.0 Search vendor "Discourse" for product "Discourse" and version "2.8.0"		beta3		Affected
Discourse Search vendor "Discourse"		Discourse Search vendor "Discourse" for product "Discourse"				2.8.0 Search vendor "Discourse" for product "Discourse" and version "2.8.0"		beta4		Affected