Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network's hosts as well as services running on the user's local machine utilizing WebRTC connections. This vulnerability affects Firefox ESR < 78.9, Thunderbird < 78.9, and Firefox < 87.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-23982
• https://bugzilla.mozilla.org/show_bug.cgi?id=1677046
• https://security.gentoo.org/glsa/202104-09
• https://security.gentoo.org/glsa/202104-10
• https://www.mozilla.org/security/advisories/mfsa2021-10/
• https://www.mozilla.org/security/advisories/mfsa2021-11/
• https://www.mozilla.org/security/advisories/mfsa2021-12/