CVE-2021-30657Known exploitationPublic exploit

Gatekeeper bypass via misclassified script app bundles

Published Sep 8, 2021 · Updated Oct 21, 2025

Gatekeeper bypass in Apple macOS allows attackers to run unsigned code after user launch on Big Sur before 11.3 or unpatched Catalina. syspolicyd misclassifies a script-based .app bundle without Info.plist as not a bundle, skips policy prompts, and marks it allowed. A user must open the downloaded app; its script then executes without Gatekeeper, quarantine, or notarization prompts.

CVSS severity5.5
Medium
EPSS probability68.53%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Gatekeeper bypass in Apple macOS allows attackers to run unsigned code after user launch on Big Sur before 11.3 or unpatched Catalina. syspolicyd misclassifies a script-based .app bundle without Info.plist as not a bundle, skips policy prompts, and marks it allowed. A user must open the downloaded app; its script then executes without Gatekeeper, quarantine, or notarization prompts.

The record

CVE
CVE-2021-30657
Published
Sep 8, 2021
Updated
Oct 21, 2025
Vendor
Apple
Product
macOS
Classifications
CWE-494, T1553.001, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 2025Record 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 <11.3
  2. Affected versionversion=unspecified <2021

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · macOSversion=unspecified <11.3; version=unspecified <2021

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 exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-494Download of Code Without Integrity Check
T1553.001Gatekeeper Bypass
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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