CVE-2021-29944

Name: CVE-2021-29944
Creator: NVD / NIST
Published: 2021-06-24T14:15:09.73+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.70%

Last modified Jun 17, 2026

CVE-2021-29944 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Lack of escaping allowed HTML injection when a webpage was viewed in Reader View. While a Content Security Policy prevents direct code execution, HTML injection is still possible. EPSS estimates a 0.70% chance of exploitation in the next 30 days.

Description

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View. While a Content Security Policy prevents direct code execution, HTML injection is still possible. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 88.

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

0.70%

48.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 88.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1697604Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-16/Release Notes, Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1697604Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-16/Release Notes, Vendor Advisory

Timeline

Published: Jun 24, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-29944?

How severe is CVE-2021-29944?

CVE-2021-29944 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.70% probability of exploitation in the next 30 days.

How do I fix CVE-2021-29944?

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-2021-29944?

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

Scan your code now

Source: NVD / NIST