CVE-2024-54538Public exploitNetwork attack vector

System-wide hang via unconstrained certificate path validation

Published Dec 20, 2024 · Updated Apr 2, 2026

Certificate-validation denial of service in affected Apple operating systems allows remote attackers to cause a system-wide hang. The Security framework's trustd process performs unconstrained nested comparisons between certificate subject alternative names and higher-chain name constraints, exhausting CPU. A crafted S/MIME email can trigger validation without user interaction in macOS Mail; the published demonstration establishes persistent hangs on macOS, while Apple reports denial of service on the other affected platforms.

CVSS severity7.5
High
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Certificate-validation denial of service in affected Apple operating systems allows remote attackers to cause a system-wide hang. The Security framework's trustd process performs unconstrained nested comparisons between certificate subject alternative names and higher-chain name constraints, exhausting CPU. A crafted S/MIME email can trigger validation without user interaction in macOS Mail; the published demonstration establishes persistent hangs on macOS, while Apple reports denial of service on the other affected platforms.

The record

CVE
CVE-2024-54538
Published
Dec 20, 2024
Updated
Apr 2, 2026
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 2026Record 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=0 <17.7.1
  2. Affected versionversion=0 <18.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=0 <17.7.1; version=0 <18.1
Apple · visionOSversion=0 <2.1
Apple · tvOSversion=0 <18.1
Apple · macOSversion=0 <13.7.1; version=0 <14.7.1; version=0 <15.1
Apple · watchOSversion=0 <11.1

Published CVSS scores

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

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 exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

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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