CVE-2020-9823Network attack vector

Conversation state alteration after participant removal

Published Jun 9, 2020 · Updated Aug 4, 2024

Improper state validation in Apple iOS before 13.5 allows remote authenticated users removed from an iMessage conversation to alter its state. Apple identifies the Messages component and improved checks but does not disclose which state-changing operation or membership check is defective. The attacker must previously have participated in the conversation; the disclosed consequence is limited to altering conversation state after removal.

CVSS severity7.5
High
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper state validation in Apple iOS before 13.5 allows remote authenticated users removed from an iMessage conversation to alter its state. Apple identifies the Messages component and improved checks but does not disclose which state-changing operation or membership check is defective. The attacker must previously have participated in the conversation; the disclosed consequence is limited to altering conversation state after removal.

The record

CVE
CVE-2020-9823
Published
Jun 9, 2020
Updated
Aug 4, 2024
Vendor
Apple
Product
iOS
Classifications
Unavailable
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 9, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 <iOS 13.5 and iPadOS 13.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Apple · iOSversion=unspecified <iOS 13.5 and iPadOS 13.5

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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