CVE-2026-43820

HIGH CVSS 3.1: 7.7 EPSS 0.08%
Updated Jul 25, 2026
NIOSSLCertificate
Parameter Value
CVSS 7.7 (HIGH)
Type CWE-125 (Out-of-bounds Read)
Vendor NIOSSLCertificate
Public PoC No

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.

Attack Parameters

Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Weakness Type (CWE)