CVE-2021-41095

XSS via blocked watched word in error message

Severity Score

6.1

*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 discussion platform. There is a cross-site scripting (XSS) vulnerability in versions 2.7.7 and earlier of the `stable` branch, versions 2.8.0.beta6 and earlier of the `beta` branch, and versions 2.8.0.beta6 and earlier of the `tests-passed` branch. Rendering of some error messages that contain user input can be susceptible to XSS attacks. This vulnerability only affects sites which have blocked watched words that contain HTML tags, modified or disabled Discourse's default Content Security Policy. This issue is patched in the latest `stable`, `beta` and `tests-passed` versions of Discourse. As a workaround, avoid modifying or disabling Discourse’s default Content Security Policy, and blocking watched words containing HTML tags.

Discourse es una plataforma de debate de código abierto. Se presenta una vulnerabilidad de tipo cross-site scripting (XSS) en versiones 2.7.7 y anteriores de la rama "stable", en las versiones 2.8.0.beta6 y anteriores de la rama "beta", y en las versiones 2.8.0.beta6 y anteriores de la rama "tests-passed". La representación de algunos mensajes de error que contienen entradas del usuario puede ser susceptible de ataques de tipo XSS. Esta vulnerabilidad sólo afecta a los sitios que han bloqueado las palabras vigiladas que contienen etiquetas HTML, han modificado o han deshabilitado la política de seguridad de contenidos predeterminada de Discourse. Este problema está parcheado en las últimas versiones "stable", "beta" y "tests-passed" de Discourse. Como solución, evite la modificar o desactivar la política de seguridad de contenidos predeterminada de Discourse y bloquear las palabras vigiladas que contengan etiquetas HTML

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-09-15 CVE Reserved
2021-09-27 CVE Published
2024-06-12 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 (2)

URL	Tag	Source
https://github.com/discourse/discourse/security/advisories/GHSA-qvqx-2h7w-m479	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://github.com/discourse/discourse/pull/14434/commits/40b776b9d39c41d9273d01eecf8fe03aa39fcb59	2023-11-07

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"				<= 2.7.7 Search vendor "Discourse" for product "Discourse" and version " <= 2.7.7"		-		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
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"		beta5		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"		beta6		Affected