CVE-2020-26293

Name: CVE-2020-26293
Creator: NVD / NIST
Published: 2021-01-04T19:15:14.97+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 1.00%

Last modified Jun 17, 2026

CVE-2020-26293 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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. EPSS estimates a 1.00% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

1.00%

58.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Htmlsanitizer Project	Htmlsanitizer	< 5.0.372

References

https://github.com/mganss/HtmlSanitizer/commit/a3a7602a44d4155d51ec0fbbedc2a49e9c7e2eb8Patch, Third Party Advisory
https://github.com/mganss/HtmlSanitizer/releases/tag/v5.0.372Release Notes, Third Party Advisory
https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-8j9v-h2vp-2hhvThird Party Advisory
https://www.nuget.org/packages/HtmlSanitizer/Product, Third Party Advisory
https://github.com/mganss/HtmlSanitizer/commit/a3a7602a44d4155d51ec0fbbedc2a49e9c7e2eb8Patch, Third Party Advisory
https://github.com/mganss/HtmlSanitizer/releases/tag/v5.0.372Release Notes, Third Party Advisory
https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-8j9v-h2vp-2hhvThird Party Advisory
https://www.nuget.org/packages/HtmlSanitizer/Product, Third Party Advisory

Timeline

Published: Jan 4, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26293?

How severe is CVE-2020-26293?

CVE-2020-26293 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 1.00% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26293?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26293?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST