CVE-2020-26961 Information

Description

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Reference

https://www.mozilla.org/security/advisories/mfsa2020-50/ https://www.mozilla.org/security/advisories/mfsa2020-51/ https://www.mozilla.org/security/advisories/mfsa2020-52/ https://bugzilla.mozilla.org/show_bug.cgi?id=1672528

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

NONE

Base Severity

6.5