CVE-2025-5963

TCC bypass via permissive code-signing entitlements

Published Jun 20, 2025 · Updated Jun 20, 2025

Incorrect default permissions in Postbox 7.0.65 allow local users to bypass TCC by injecting a dynamic library into the macOS app. The signed application carries entitlements that permit DYLD environment variables and disable library validation, allowing DYLD_INSERT_LIBRARIES to load attacker-controlled code in the application's context. An unprivileged local account is sufficient to access resources already granted to Postbox; access to additional resources requires interaction with a macOS permission prompt.

CVSS severity4.8
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect default permissions in Postbox 7.0.65 allow local users to bypass TCC by injecting a dynamic library into the macOS app. The signed application carries entitlements that permit DYLD environment variables and disable library validation, allowing DYLD_INSERT_LIBRARIES to load attacker-controlled code in the application's context. An unprivileged local account is sufficient to access resources already granted to Postbox; access to additional resources requires interaction with a macOS permission prompt.

The record

CVE
CVE-2025-5963
Published
Jun 20, 2025
Updated
Jun 20, 2025
Vendor
Postbox, Inc.
Product
Postbox
Classifications
CWE-276, T1574.006
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 20, 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=7.0.65

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Postbox, Inc. · Postboxversion=7.0.65

Published CVSS scores

4.8CERT.PLCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-276Incorrect Default Permissions
T1574.006Hijack Execution Flow: Dynamic Linker Hijacking

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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