CVE-2021-23974: XSS

Published Feb 23, 2021
·
Updated

The DOMParser API did not properly process '<noscript>' elements for escaping. This could be used as an mXSS vector to bypass an HTML Sanitizer. This vulnerability affects Firefox < 86.

Other sources

The DOMParser API did not properly process <noscript> elements for escaping. This could be used as an mXSS vector to bypass an HTML Sanitizer.

— Mozilla

Affected Software

17 affected componentsFixes available
Mozilla Firefox<86
86
Mozilla Firefox<86.0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/firefox<87.0-r0
87.0-r0
alpine/librewolf<87.0-r0
87.0-r0
alpine/librewolf<87.0-r0
87.0-r0
alpine/librewolf<87.0-r0
87.0-r0
alpine/librewolf<87.0-r0
87.0-r0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 86
  2. Upgrade

    Upgrade alpine/firefox to a version that resolves this vulnerability.

    Fixed in 87.0-r0
  3. Upgrade

    Upgrade alpine/librewolf to a version that resolves this vulnerability.

    Fixed in 87.0-r0

Event History

Feb 23, 2021
CVE Published
12:00 AM
Feb 26, 2021
CVE Published
via MITRE·01:51 AM
Data Sourced
via MITRE·01:51 AM
DescriptionWeakness
Data Sourced
via NVD·02:15 AM
DescriptionSeverityAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2021-23974?

CVE-2021-23974 has been classified as a moderate severity vulnerability.

2

How do I fix CVE-2021-23974?

To fix CVE-2021-23974, update your Firefox browser to version 86 or later.

3

Which versions of Firefox are affected by CVE-2021-23974?

CVE-2021-23974 affects Firefox versions earlier than 86.

4

What type of vulnerability is CVE-2021-23974?

CVE-2021-23974 is a reflected Cross-Site Scripting (mXSS) vulnerability.

5

Can CVE-2021-23974 be exploited easily?

Yes, CVE-2021-23974 can be exploited to bypass an HTML sanitizer, making it a potential attack vector.

Contact

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