CVE-2021-30943Network attack vector

Message disclosure via stale group membership

Published Aug 24, 2021 · Updated Aug 3, 2024

Authorization flaw in Messages in Apple watchOS before 8.3 allows remote authenticated users to keep receiving messages after leaving a group. The group-membership handler fails to revoke message delivery when a member leaves, so the former member remains subscribed to group traffic. The user must first belong to the group; the disclosed impact is continued receipt of subsequent messages, not modification or deletion.

CVSS severity4.3
Medium
EPSS probability0.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization flaw in Messages in Apple watchOS before 8.3 allows remote authenticated users to keep receiving messages after leaving a group. The group-membership handler fails to revoke message delivery when a member leaves, so the former member remains subscribed to group traffic. The user must first belong to the group; the disclosed impact is continued receipt of subsequent messages, not modification or deletion.

The record

CVE
CVE-2021-30943
Published
Aug 24, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
watchOS
Classifications
CWE-613
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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 <12.1
  2. Affected versionversion=unspecified <15.2
  3. Affected versionversion=unspecified <8.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Apple · watchOSversion=unspecified <12.1; version=unspecified <15.2; version=unspecified <8.3

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-613Insufficient Session Expiration

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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