Apple Swiftnio SSL vulnerabilities

2 CVEs affecting Apple Swiftnio SSL, 0 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2026-43820, published 2026-07-23.

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Known exploited (CISA KEV) first, then by EPSS exploit probability.

• CVE-2019-8849, published 2019-12-18. Critical severity, CVSS 9.8. EPSS: 2.2% chance of exploitation in the next 30 days. The issue was addressed by signaling that an executable stack is not required. This issue is fixed in SwiftNIO SSL 2.4.1. A SwiftNIO application using TLS may be able to execute arbitrary code.
• CVE-2026-43820, published 2026-07-23. High severity, CVSS 7.7. EPSS: 0.1% chance of exploitation in the next 30 days. 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…