CVE-2021-36773: Debian Linux

High severity, CVSS 7.5. EPSS: 1.3% chance of exploitation in the next 30 days.

uBlock Origin before 1.36.2 and nMatrix before 4.4.9 support an arbitrary depth of parameter nesting for strict blocking, which allows crafted web sites to cause a denial of service (unbounded recursion that can trigger memory consumption and a loss of all blocking functionality).

Affected products

• Debian Debian Linux: version 9.0 only
• Sciruby Nmatrix: before 4.4.9 (fixed in 4.4.9)
• Ublockorigin Ublock Origin: before 1.36.2 (fixed in 1.36.2)
• Umatrix Project Umatrix: before 1.4.2 (fixed in 1.4.2)

Published 2021-07-18. Last modified 2026-06-17.