CVE-2026-28815: Apple swift-crypto out-of-bounds read in X-Wing HPKE decapsulation

CVE-2026-28815 · Severity: high · CVSS 7.5 · Published 2026-04-03

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.

Technologies: Apple Swift Crypto. Vendors: Apple.

Quick answers

Is CVE-2026-28815 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-28815 being exploited in the wild.
How severe is CVE-2026-28815?
High severity, with a CVSS score of 7.5, published 3 April 2026.
Which products and versions are affected?
Apple Swift Crypto 4.0.0 - 4.3.0.
Is there a fix for CVE-2026-28815?
A patch was published on 2026-04-03: Fix confirmed in version 4.3.1 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-28815 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-28815?
Check whether you run Apple Swift Crypto at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

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

References

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