An out-of-bounds write was discovered in Apple’s handling of asset catalog files. The flaw arises from insufficient bounds checking during catalog parsing, allowing a maliciously crafted catalog to overwrite memory beyond its intended buffer. When an affected process parses such a catalog, it can terminate unexpectedly, leading to a denial of service. This weakness corresponds to an out-of-bounds write, a classic buffer corruption flaw (CWE-787).

The issue affects Apple devices running iOS 27 and iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS OS 27, visionOS 27, and watchOS 27. All these operating systems require the specified updates to contain the patch that restores proper bounds checking in catalog processing.

The EPSS score is <1% and the vulnerability is not listed in CISA’s KEV catalog, indicating limited known exploitation so far. However, an attacker who can supply a malicious asset catalog could trigger the out-of-bounds write, causing an application or the system to crash. Because the vulnerability requires the processing of a specially crafted catalog, the attack vector is likely local or through a compromised application that loads such a file. The risk remains moderate until more information on exploitation emerges, but applying the patch is the prudent measure.