NIOSSLCertificate OOB UB via non-ASN1_STRING SANs in swift-nio-ssl <2.37.2
CVE-2026-43820 Published on July 23, 2026
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.
Products Associated with CVE-2026-43820
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Affected Versions
Apple swift-nio-ssl:- Before 2.37.2 is affected.