CVE-2021-43544

Name: CVE-2021-43544
Creator: NVD / NIST
Published: 2021-12-08T22:15:09.997+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.51%

Last modified Jun 17, 2026

CVE-2021-43544 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. When receiving a URL through a SEND intent, Firefox would have searched for the text, but subsequent usages of the address bar might have caused the URL to load unintentionally, which could lead to XSS and spoofing attacks. *This bug only affects Firefox for Android. EPSS estimates a 0.51% chance of exploitation in the next 30 days.

Description

When receiving a URL through a SEND intent, Firefox would have searched for the text, but subsequent usages of the address bar might have caused the URL to load unintentionally, which could lead to XSS and spoofing attacks. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 95.

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

0.51%

39.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 95.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1739934Issue Tracking, Permissions Required
https://www.mozilla.org/security/advisories/mfsa2021-52/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1739934Issue Tracking, Permissions Required
https://www.mozilla.org/security/advisories/mfsa2021-52/Vendor Advisory

Timeline

Published: Dec 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-43544?

How severe is CVE-2021-43544?

CVE-2021-43544 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.51% probability of exploitation in the next 30 days.

How do I fix CVE-2021-43544?

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-2021-43544?

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

Scan your code now

Source: NVD / NIST