Vulnerability Details 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 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 1.4%
CVSS Severity
CVSS v3 Score 7.7
References
Products affected by CVE-2026-43820
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cpe:2.3:a:apple:swiftnio_ssl:2.18.0
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cpe:2.3:a:apple:swiftnio_ssl:2.19.0
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cpe:2.3:a:apple:swiftnio_ssl:2.20.0
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cpe:2.3:a:apple:swiftnio_ssl:2.20.1
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cpe:2.3:a:apple:swiftnio_ssl:2.20.2
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cpe:2.3:a:apple:swiftnio_ssl:2.21.0
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cpe:2.3:a:apple:swiftnio_ssl:2.22.0
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cpe:2.3:a:apple:swiftnio_ssl:2.22.1
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cpe:2.3:a:apple:swiftnio_ssl:2.23.0
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cpe:2.3:a:apple:swiftnio_ssl:2.23.1
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cpe:2.3:a:apple:swiftnio_ssl:2.24.0
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cpe:2.3:a:apple:swiftnio_ssl:2.25.0
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cpe:2.3:a:apple:swiftnio_ssl:2.26.0
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cpe:2.3:a:apple:swiftnio_ssl:2.27.0
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cpe:2.3:a:apple:swiftnio_ssl:2.27.1
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cpe:2.3:a:apple:swiftnio_ssl:2.27.2
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cpe:2.3:a:apple:swiftnio_ssl:2.28.0
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cpe:2.3:a:apple:swiftnio_ssl:2.29.0
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cpe:2.3:a:apple:swiftnio_ssl:2.29.1
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cpe:2.3:a:apple:swiftnio_ssl:2.29.2
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cpe:2.3:a:apple:swiftnio_ssl:2.29.3
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cpe:2.3:a:apple:swiftnio_ssl:2.30.0
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cpe:2.3:a:apple:swiftnio_ssl:2.31.0
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cpe:2.3:a:apple:swiftnio_ssl:2.32.0
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cpe:2.3:a:apple:swiftnio_ssl:2.33.0
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cpe:2.3:a:apple:swiftnio_ssl:2.34.0
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cpe:2.3:a:apple:swiftnio_ssl:2.34.1
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cpe:2.3:a:apple:swiftnio_ssl:2.35.0
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cpe:2.3:a:apple:swiftnio_ssl:2.36.0
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cpe:2.3:a:apple:swiftnio_ssl:2.36.1
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cpe:2.3:a:apple:swiftnio_ssl:2.37.0
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cpe:2.3:a:apple:swiftnio_ssl:2.37.1