CVE-2020-3866

Gatekeeper bypass via attacker-controlled NFS mount

Published Feb 27, 2020 · Updated Aug 4, 2024

Gatekeeper bypass in Apple macOS before Catalina 10.15.3 allows remote attackers to evade file checks through a controlled NFS mount. Within the autofs component, Gatekeeper applies insufficient checks to files mounted through a network share, so searching for and opening such a file avoids its normal verification. Exploitation requires an attacker-controlled NFS mount and user interaction to search for and open the file, allowing untrusted content to pass Gatekeeper checks.

CVSS severity5.5
Medium
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Gatekeeper bypass in Apple macOS before Catalina 10.15.3 allows remote attackers to evade file checks through a controlled NFS mount. Within the autofs component, Gatekeeper applies insufficient checks to files mounted through a network share, so searching for and opening such a file avoids its normal verification. Exploitation requires an attacker-controlled NFS mount and user interaction to search for and open the file, allowing untrusted content to pass Gatekeeper checks.

The record

CVE
CVE-2020-3866
Published
Feb 27, 2020
Updated
Aug 4, 2024
Vendor
Apple
Product
macOS
Classifications
T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 27, 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 <macOS Catalina 10.15.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · macOSversion=unspecified <macOS Catalina 10.15.3

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
4.3NIST NVDAV:N/AC:M/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1204.002Malicious File

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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