CVE-2021-24042Network attack vector

Memory corruption via one-to-one call handling

Published Jan 4, 2022 · Updated May 22, 2025

Out-of-bounds write in Meta WhatsApp clients allows attackers to corrupt client memory when a user places a one-to-one call. Affected releases are WhatsApp and WhatsApp Business before 2.21.23 on Android and before 2.21.230 on iOS, plus WhatsApp before 2.2143 on KaiOS. The calling logic writes beyond a heap buffer during the call; Meta has not disclosed the function, processed call data, or consequences beyond memory corruption.

CVSS severity9.8
Critical
EPSS probability1.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Meta WhatsApp clients allows attackers to corrupt client memory when a user places a one-to-one call. Affected releases are WhatsApp and WhatsApp Business before 2.21.23 on Android and before 2.21.230 on iOS, plus WhatsApp before 2.2143 on KaiOS. The calling logic writes beyond a heap buffer during the call; Meta has not disclosed the function, processed call data, or consequences beyond memory corruption.

The record

CVE
CVE-2021-24042
Published
Jan 4, 2022
Updated
May 22, 2025
Vendor
Meta Platforms, Inc.
Product
WhatsApp for KaiOS
Classifications
CWE-122, CWE-787
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 4, 2022CVE publishedPublication date reported by the CVE source.
  2. May 22, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <v2.2143

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Meta Platforms, Inc. · WhatsApp for KaiOSversion=unspecified <v2.2143
Meta Platforms, Inc. · WhatsApp for Androidversion=unspecified <v2.21.23
Meta Platforms, Inc. · WhatsApp Business for Androidversion=unspecified <v2.21.23
Meta Platforms, Inc. · WhatsApp for iOSversion=unspecified <v2.21.230
Meta Platforms, Inc. · WhatsApp Business for iOSversion=unspecified <v2.21.230

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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