What is CVE-2021-23959?

CVE-2021-23959 is a medium-severity vulnerability in Mozilla Firefox, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-02-26.

How severe is CVE-2021-23959?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Mozilla Firefox

CVE-2021-23959

An XSS bug in internal error pages could have led to various spoofing attacks, including other error pages and the address bar. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 85.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.006 (43.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Mozilla Firefox — versions < 85

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

security@mozilla.org (x_refsource_MISC, Release Notes, Vendor Advisory)
security@mozilla.org (Permissions Required, x_refsource_MISC, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2021-23959?: CVE-2021-23959 is a medium-severity vulnerability in Mozilla Firefox, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-02-26.
How severe is CVE-2021-23959?: Medium severity. CVSS v3 base score is 6.1 out of 10.