CVE-2022-31106: Clever Underscore.deep

Critical severity, CVSS 9.8. EPSS: 1.1% chance of exploitation in the next 30 days.

Underscore.deep is a collection of Underscore mixins that operate on nested objects. Versions of `underscore.deep` prior to version 0.5.3 are vulnerable to a prototype pollution vulnerability. An attacker can craft a malicious payload and pass it to `deepFromFlat`, which would pollute any future Objects created. Any users that have `deepFromFlat` or `deepPick` (due to its dependency on `deepFromFlat`) in their code should upgrade to version 0.5.3 as soon as possible. Users unable to upgrade may mitigate this issue by modifying `deepFromFlat` to prevent specific keywords which will prevent this from happening.

Affected products

• Clever Underscore.deep: before 0.5.3 (fixed in 0.5.3)

Published 2022-06-28. Last modified 2026-06-17.