CVE-2024-42220Public exploit

Permission bypass via disabled library validation

Published Dec 18, 2024 · Updated Dec 19, 2024

Library injection in Microsoft Outlook 16.83.3 for macOS allows local users to reuse the application's permissions via a crafted library. Outlook carries the com.apple.security.cs.disable-library-validation entitlement, so its hardened runtime accepts unsigned dynamic libraries. Exploitation requires a local malicious application to copy and launch Outlook; injected code then inherits permissions already granted to Outlook without another prompt.

CVSS severity7.1
High
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Library injection in Microsoft Outlook 16.83.3 for macOS allows local users to reuse the application's permissions via a crafted library. Outlook carries the com.apple.security.cs.disable-library-validation entitlement, so its hardened runtime accepts unsigned dynamic libraries. Exploitation requires a local malicious application to copy and launch Outlook; injected code then inherits permissions already granted to Outlook without another prompt.

The record

CVE
CVE-2024-42220
Published
Dec 18, 2024
Updated
Dec 19, 2024
Vendor
Microsoft
Product
Microsoft Outlook
Classifications
CWE-347, T1574.006
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 18, 2024CVE publishedPublication date reported by the CVE source.
  2. Dec 19, 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=16.83.3 for macOS

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft Outlookversion=16.83.3 for macOS

Published CVSS scores

9.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
7.1Cisco TalosCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1574.006Dynamic Linker Hijacking

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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