Vulnerability 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 Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 83.0 |
| Mozilla | Firefox Esr | < 78.5 |
| Mozilla | Thunderbird | < 78.5 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1672528Issue TrackingPermissions RequiredVendor 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/Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1672528Issue TrackingPermissions RequiredVendor 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/Vendor Advisory
FAQ
What is CVE-2020-26961?
CVE-2020-26961 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 ...
How severe is CVE-2020-26961?
CVE-2020-26961 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2020-26961?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.