Xcode Binary Parsing and Sandbox Escape Flaws

Apple Xcode before version 27 fails to enforce library validation on certain bundled binaries, allowing a malicious app already running inside Xcode's sandbox to load untrusted libraries and break out of that sandbox (CVSS 8.8, scope-changed, high confidentiality/integrity/availability impact). Exploitation is strictly local: an attacker must first get code executing on the macOS host - for example through a trojanized developer tool, plugin, or dependency - and the flaw then provides sandbox escape and privilege escalation rather than initial access. Apple addressed the issue by enforcing library validation, shipping the fix in Xcode 27 (available from https://support.apple.com/en-us/149040); no public exploit code and no confirmed active exploitation were identified at time of analysis.

Parsing a maliciously crafted binary in Apple Xcode prior to version 27 can terminate the IDE unexpectedly, giving an attacker who convinces a developer to open a booby-trapped file a denial-of-service primitive against the developer's workstation. The flaw is an input-validation weakness (CWE-20) in Xcode's binary-parsing path and requires user interaction - the victim must actively load the crafted artifact - with impact limited to application availability (A:L only, no confidentiality, integrity, or code-execution consequences). Independent signals agree on low priority: EPSS is 0.15% (3rd percentile), CISA SSVC records exploitation as none and automatable as no, there is no KEV listing, and no public exploit code has been identified at time of analysis. Note that the supplied base vector (AV:N) is more permissive than our assessed local attack vector (AV:L); the practical threat model is social engineering a developer into opening the file rather than a remotely reachable service.

An out-of-bounds read in Apple Xcode's binary-parsing tools affects Xcode installs earlier than 27 and can terminate the affected tool when it processes a maliciously crafted binary, producing a local denial-of-service condition. The authoritative assessment is local access with no privileges required but user interaction required, and impact limited to availability (C:N/I:N/A:L); there is no network-exposed unauthenticated path and no confirmed data disclosure. No public exploit was identified at time of analysis, EPSS is 0.15% (3rd percentile), and SSVC lists exploitation as none, so this is a low-priority developer-workstation issue.

This issue was addressed by enforcing library validation on the affected binaries. This issue is fixed in Xcode 27. An app may be able to break out of its sandbox.