CVE-2021-23961: Debian Linux

High severity, CVSS 7.4. EPSS: 1.5% chance of exploitation in the next 30 days.

Further techniques that built on the slipstream research combined with a malicious webpage could have exposed both an internal network's hosts as well as services running on the user's local machine. This vulnerability affects Firefox < 85.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only
• Mozilla Firefox: before 85.0 (fixed in 85.0)

Published 2021-02-26. Last modified 2026-06-17.