CVE-2026-28815 Swift Crypto: X-Wing HPKE Decapsulation Accepts Malformed Ciphertext Length

High 7.5 Published 3 Apr 2026 Updated 3 Apr 2026

A remote attacker can trigger an out-of-bounds read in the swift-crypto library, potentially causing crashes or memory disclosure.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-28815?

CVE-2026-28815 is a high-severity vulnerability in Apple macOS, published on 3 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A remote attacker can supply a short X-Wing HPKE encapsulated key and trigger an out-of-bounds read in the C decapsulation path, potentially causing a crash or memory disclosure depending on runtime protections. This issue is fixed in swift-crypto version 4.3.1.

Weakness: CWE-125

Which versions are affected by CVE-2026-28815?

2 open source packages ship an affected version, including swift-crypto. It affects 1 product.

Package	Affected	Fixed in
`swift-crypto` SwiftURL	From `4.0.0`	`4.3.1`
`swift-crypto` SwiftURL	From `4.0.0`	`4.3.1`

Products include Apple Swift-Crypto.

How do I fix CVE-2026-28815?

Upgrade swift-crypto to 4.3.1 or later.

Is CVE-2026-28815 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-28815 exists.

CVE-2026-43823 When initializing an RSA public key from DER or PEM bytes throws an error, the EVP_PKEY* is double-freed: first in the catch block, then in the deinit. High 7.5

Sources

Also known as GHSA-9m44-rr2w-ppp7.