Executive brief
Apple's swift-crypto library, which provides cryptographic functions for Swift applications, contains a vulnerability in its handling of secure keys. An attacker can send a specially crafted, shortened key to an application using this library, potentially causing the application to crash or leak sensitive information from its memory. This could lead to service outages or the exposure of private data.
Technical details
An out-of-bounds read vulnerability exists in the X-Wing HPKE decapsulation path of the swift-crypto library. The root cause is a failure to validate the length of attacker-controlled encapsulated ciphertext before passing it to a C-based API. The underlying C code expects a fixed-size buffer of 1120 bytes; when a shorter Swift 'Data' object is provided, the Foreign Function Interface (FFI) boundary is breached, leading to a read beyond the allocated buffer. This can be triggered remotely during the initialization of an 'HPKE.Recipient' object. The flaw can result in a denial-of-service (crash) or potential memory disclosure. The issue is resolved in version 4.3.1.
Affected products
- Apple swift-crypto 4.0.0 - 4.3.0
Timeline
- 2026-04-01: advisory: GitHub advisory published by Apple
- 2026-04-02: disclosed: CVE published to NVD
- 2026-04-03: patched: Fix confirmed in version 4.3.1