CVE-2020-26293

Possible XSS bypass if style tag is allowed

MEDIUM
6.1
CVSS Score
Published: January 4, 2021 at 06:20 PM UTC
Updated: June 17, 2026 at 03:08 AM UTC
2 products affected across 2 vendorsHtmlsanitizerHtmlSanitizer

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Severity
MEDIUM6.1
Exploit prediction
EPSS 1%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.0.372
Affected range stops below 5.0.372, so it looks safe — our inference, not a vendor statement
v < 5.0.372
Affected range stops below 5.0.372, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

6.1MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-74CWE-79

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