CVE-2020-26293

Possible XSS bypass if style tag is allowed

Severity Score

6.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. In HtmlSanitizer before version 5.0.372, there is a possible XSS bypass if style tag is allowed. If you have explicitly allowed the `<style>` tag, an attacker could craft HTML that includes script after passing through the sanitizer. The default settings disallow the `<style>` tag so there is no risk if you have not explicitly allowed the `<style>` tag. The problem has been fixed in version 5.0.372.

HtmlSanitizer es una biblioteca .NET para limpiar fragmentos HTML y documentos de construcciones que pueden conllevar a ataques de tipo XSS. En HtmlSanitizer versiones anteriores a 5.0.372, se presenta una posible omisión de XSS si la etiqueta de estilo es permitida. Si ha permitido explícitamente la etiqueta "(style)", un atacante podría crear HTML que incluya un script después de pasar a través del sanitizador. La configuración predeterminada no permite la etiqueta "(style)", por lo que no existe riesgo si no ha permitido explícitamente la etiqueta "(style)". El problema ha sido corregido en la versión 5.0.372.

*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

Changed

Confidentiality

None

Integrity

High

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

2020-10-01 CVE Reserved
2021-01-04 CVE Published
2024-08-04 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CAPEC

References (4)

URL	Tag	Source
https://github.com/mganss/HtmlSanitizer/releases/tag/v5.0.372	Release Notes
https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-8j9v-h2vp-2hhv	Third Party Advisory
https://www.nuget.org/packages/HtmlSanitizer	Product

URL	Date	SRC

URL	Date	SRC
https://github.com/mganss/HtmlSanitizer/commit/a3a7602a44d4155d51ec0fbbedc2a49e9c7e2eb8	2021-01-07

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Htmlsanitizer Project Search vendor "Htmlsanitizer Project"		Htmlsanitizer Search vendor "Htmlsanitizer Project" for product "Htmlsanitizer"				< 5.0.372 Search vendor "Htmlsanitizer Project" for product "Htmlsanitizer" and version " < 5.0.372"		-		Affected