Medium severity · published Dec 9, 2020
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
6.5
CVSS
1.2%
EPSS
No
On KEV
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
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.2% · higher than 67% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 83.0 · source: NVD
FE
Firefox Esr · Mozilla
before 78.5 · source: NVD
TH
Thunderbird · Mozilla
before 78.5 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-26961
CVE.org
https://www.cve.org/CVERecord?id=CVE-2020-26961
Issue Tracking
https://bugzilla.mozilla.org/show_bug.cgi?id=1672528
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-50/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-51/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-52/
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