CVE-2026-43820

A flaw was found in swift-nio-ssl. This vulnerability arises from the improper handling of Subject Alternative Names SANs within SSL certificates. When processing SANs that are not backed by an ASN1STRING, the system attempts to access memory outside of its allocated buffer, leading to an...

CVE-2026-43820

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 ASN1STRING, but not all SANs are backed by ASN1STRING, so accessing the buffer for such a type can lead to out-of-bounds memory access. This...

CVE-2026-43820

The CVE-2026-43820 vulnerability affects the NIOSSL component used with SwiftNIO SSL. NIOSSLCertificate._subjectAlternativeNames exposes the raw bytes of a certificate’s SANs; NIOSSL may expose a buffer expected to be backed by an ASN1_STRING, but not all SAN types are backed accordingly, which c...