Vulnerability in Mozilla Firefox

CVE-2020-35111

When an extension with the proxy permission registered to receive <all_urls>, the proxy.onRequest callback was not triggered for view-source URLs. While web content cannot navigate to such URLs, a user opening View Source could have inadvertently leaked their IP address. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

EPSS: 0.012 (64.2th 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:L/I:N/A:N.

Affected products

References

Frequently asked questions

What is CVE-2020-35111?
CVE-2020-35111 is a medium-severity vulnerability in Mozilla Firefox. CVSS score: 4.3/10. Published 2021-01-07.
How severe is CVE-2020-35111?
Medium severity. CVSS v3 base score is 4.3 out of 10.