Auth bypass in Mozilla Firefox

CVE-2021-29961

When styling and rendering an oversized `<select>` element, Firefox did not apply correct clipping which allowed an attacker to paint over the user interface. This vulnerability affects Firefox < 89.

Vulnerability class: Broken Access Control

EPSS: 0.008 (51.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-29961?
CVE-2021-29961 is a medium-severity vulnerability in Mozilla Firefox, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2021-06-24.
How severe is CVE-2021-29961?
Medium severity. CVSS v3 base score is 4.3 out of 10.