CVE-2020-26961

MEDIUM

Firefox <83, Firefox ESR <78.5, Thunderbird <78.5 - SSRF

Title source: llm
STIX 2.1

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.

References (4)

Core 4
Core References
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1672528
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-50/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-52/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-51/

Scores

CVSS v3 6.5
EPSS 0.0027
EPSS Percentile 50.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Details

Status published
Products (3)
mozilla/firefox < 83.0
mozilla/firefox_esr < 78.5
mozilla/thunderbird < 78.5
Published Dec 09, 2020
Tracked Since Feb 18, 2026