CVE-2025-5963 TCC Bypass via Dylib Injection in Postbox
Local attackers can inject code into Postbox to bypass macOS TCC privacy controls and access user data, as the software is discontinued and unpatched.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-5963?
CVE-2025-5963 is a medium-severity vulnerability in Postbox, published on 20 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The Postbox's configuration on macOS, specifically the presence of entitlements: "com.apple.security.cs.allow-dyld-environment-variables" and "com.apple.security.cs.disable-library-validation" allows for Dynamic Library (Dylib) injection. A local attacker with unprivileged access can use environment variables like DYLD_INSERT_LIBRARIES to successfully inject code in application's context and bypass Transparency, Consent, and Control (TCC). Acquired resource access is limited to previously granted permissions by the user. Access to other resources beyond granted-permissions requires user interaction with a system prompt asking for permission.
The original company behind Postbox is no longer operational, the software will no longer receive updates. The acquiring company (em Client) did not cooperate in vulnerability disclosure.
Weakness: CWE-276
Which versions are affected by CVE-2025-5963?
How do I fix CVE-2025-5963?
No fix has been published for CVE-2025-5963 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-5963 being exploited?
There is no known exploitation of CVE-2025-5963 in the wild and no public exploit code.
Sources
Also known as GHSA-jg7f-3jqj-8gj5.