Apple Xcode Integer Underflow Flaw Lets Crafted Archives Leak Memory and Crash Builds
Researchers disclosed an integer underflow in Apple's Mach-O archive parser that lets crafted static libraries crash Xcode builds or leak process memory.
SecureLayer7 disclosed an integer underflow in the mach_o::Archive::Entry::name() function in Apple's open-source dyld project, reported to Apple Product Security on May 23, 2026, with no public patch after more than 90 days. Crafted static archives (.a files) cause the parser's unsigned index to wrap to SIZE_MAX, producing SIGSEGV crashes in the ld-prime linker, out-of-bounds reads that may print adjacent memory to stderr, or SIGABRT in libtool and ranlib. The modern parser is used by ld-prime, the default linker for arm64, arm64e, and x86_64 since Xcode 15, while legacy ld-classic is unaffected. Crafted archives need only be processed, creating supply-chain risk via vendored SDKs, binary dependencies, and CI pipelines.
Xcode 27.2 beta (27B5019j)
Apple released Xcode 27.2 beta build 27B5019j to developers for testing.
Apple has published Xcode 27.2 beta build 27B5019j on its developer release portal, with downloads and release notes available. The notice contains no security advisories or CVE information.
Xcode 27 (27A266a)
Apple released Xcode 27 (build 27A266a) with no security fixes detailed in the announcement.
Apple published Xcode 27 (27A266a) on its developer news feed. The notice contains only download and release-note links. No security content is described in the announcement itself.
Xcode 27 RC (27A266a)
Apple released the Xcode 27 release candidate (build 27A266a) via its developer releases page.
Apple has published a release candidate of Xcode 27, build 27A266a, on its developer releases page. The listing contains no security notes, CVEs, or vulnerability details in the available text. This is a routine vendor software release ahead of the final Xcode 27 version.
Apple Rolls Out Massive Security Update Fixing 273 Vulnerabilities Across Its Devices
Apple's coordinated rollout patches 273 unique vulnerabilities across iOS 27, macOS Golden Gate 27, watchOS and Safari, including remote code execution flaws.
Apple shipped one of its largest coordinated security updates on September 14, 2026, fixing 273 unique CVEs across iOS 27, iPadOS 27, macOS Golden Gate 27, watchOS 27, tvOS 27, visionOS 27, Safari 27 and Xcode 27. Highlights include CVE-2026-65414, a Bluetooth out-of-bounds write enabling remote code execution, and CVE-2026-84607, an AVEVideoEncoder race condition granting kernel privileges to sandboxed apps. macOS Golden Gate 27 covers the broadest set with 210 CVEs, and Apple states none of the flaws were exploited in the wild.
The Apple Security Update Review for September 2026
Apple's September 2026 updates patch 45+ flaws, including a 9.8 Screen Sharing authentication bypass (CVE-2026-65400) already listed in CISA's KEV.
ZDI's review of Apple's September 2026 security updates catalogs dozens of CVEs across macOS, iOS, iPadOS, watchOS and other platforms. CVE-2026-65400 (CVSS 9.8) lets a network attacker authenticate to Screen Sharing Server without valid credentials and is flagged as KEV, while CVE-2026-65414 (CVSS 9.8) enables remote code execution via Bluetooth. The set also includes 8.8-rated memory corruption flaws in WebKit, WebRTC, CUPS, ImageIO and the kernel, plus sandbox escapes, privilege escalations to root, and arbitrary code execution via crafted files.