CVE-2021-30853Public exploit

Gatekeeper bypass via interpreter-less shebang

Published Aug 24, 2021 · Updated Aug 3, 2024

Gatekeeper bypass in Apple macOS Big Sur before 11.6 allows attackers to run an unsigned application after a user launches it. An interpreter-less shebang makes posix_spawnp retry the app's script through /bin/sh without invoking syspolicyd for policy evaluation. The victim must launch the downloaded app; its code then runs with the user's privileges without the expected Gatekeeper warning.

CVSS severity5.5
Medium
EPSS probability6.94%
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 Big Sur before 11.6 allows attackers to run an unsigned application after a user launches it. An interpreter-less shebang makes posix_spawnp retry the app's script through /bin/sh without invoking syspolicyd for policy evaluation. The victim must launch the downloaded app; its code then runs with the user's privileges without the expected Gatekeeper warning.

The record

CVE
CVE-2021-30853
Published
Aug 24, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
macOS
Classifications
CWE-787, T1553.001
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 <11.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · macOSversion=unspecified <11.6

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.

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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 exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1553.001Subvert Trust Controls: Gatekeeper Bypass

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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