CVE-2026-43820
High
Description
NIOSSLCertificate._subjectAlternativeNames provides access to the raw bytes for a cert's SANs. NIOSSL provides access to a buffer assumed to be backed by an ASN1_STRING, but not all SANs are backed by ASN1_STRING, so accessing the buffer for such a type can lead to out-of-bounds memory access. This vulnerability is addressed in swift-nio-ssl version 2.37.2.
SeverityHigh
CVSS7.7
Exploit probability—
Product
Apple Swiftnio Ssl
PublishedJul 23, 2026
First seenJul 23, 2026
Weakness typeCWE-125Out-of-bounds read
How to fix
Update
- apple swiftnio_ssl2.37.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| apple swiftnio_ssl | 2.18.0 ≤ v < 2.37.2 | 2.37.2 |
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