Vulnerability in Mozilla Firefox
CVE-2020-26961
When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges from the responses as these do not make sense coming from a DoH resolver. However when an IPv4 address was mapped through IPv6, these addresses were erroneously let through, leading to a potential DNS Rebinding attack. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
EPSS: 0.012 (63.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.
Affected products
- Mozilla Firefox — versions < 83
- Mozilla Firefox Esr — versions < 78.5
- Mozilla Firefox_esr
- Mozilla Thunderbird — versions < 78.5
References
- security@mozilla.org (Permissions Required, x_refsource_MISC, Issue Tracking, Vendor Advisory)
- security@mozilla.org (x_refsource_CONFIRM, Vendor Advisory)
- security@mozilla.org (x_refsource_CONFIRM, Vendor Advisory)
- security@mozilla.org (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2020-26961?
- CVE-2020-26961 is a medium-severity vulnerability in Mozilla Firefox. CVSS score: 6.5/10. Published 2020-12-09.
- How severe is CVE-2020-26961?
- Medium severity. CVSS v3 base score is 6.5 out of 10.