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. in Apple swift-nio-ssl
A vulnerability in Apple swift-nio-ssl's NIOSSLCertificate._subjectAlternativeNames allows access to raw bytes of a certificate's Subject Alternative Names (SANs). The issue arises because NIOSSL assumes the buffer is backed by an ASN1_STRING, but some SAN types are not, leading to potential out-of-bounds memory access. This flaw is fixed in swift-nio-ssl version 2.37.2.
AI Analysis
Technical Summary
The vulnerability in Apple swift-nio-ssl involves the _subjectAlternativeNames property of NIOSSLCertificate, which exposes raw bytes for a certificate's SANs. The implementation assumes that the underlying buffer is always backed by an ASN1_STRING structure. However, certain SAN types do not use ASN1_STRING backing, causing the buffer access to potentially read out-of-bounds memory. This can lead to memory safety issues such as crashes or data leakage. The issue is resolved in swift-nio-ssl version 2.37.2.
Potential Impact
This vulnerability can cause out-of-bounds memory access when processing certain SAN types in certificates, potentially leading to application crashes or unintended memory disclosure. There is no information about known exploits in the wild.
Mitigation Recommendations
Upgrade to swift-nio-ssl version 2.37.2 or later, where this vulnerability is addressed. No other mitigation is indicated by the vendor advisory.
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. in Apple swift-nio-ssl
Description
A vulnerability in Apple swift-nio-ssl's NIOSSLCertificate._subjectAlternativeNames allows access to raw bytes of a certificate's Subject Alternative Names (SANs). The issue arises because NIOSSL assumes the buffer is backed by an ASN1_STRING, but some SAN types are not, leading to potential out-of-bounds memory access. This flaw is fixed in swift-nio-ssl version 2.37.2.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in Apple swift-nio-ssl involves the _subjectAlternativeNames property of NIOSSLCertificate, which exposes raw bytes for a certificate's SANs. The implementation assumes that the underlying buffer is always backed by an ASN1_STRING structure. However, certain SAN types do not use ASN1_STRING backing, causing the buffer access to potentially read out-of-bounds memory. This can lead to memory safety issues such as crashes or data leakage. The issue is resolved in swift-nio-ssl version 2.37.2.
Potential Impact
This vulnerability can cause out-of-bounds memory access when processing certain SAN types in certificates, potentially leading to application crashes or unintended memory disclosure. There is no information about known exploits in the wild.
Mitigation Recommendations
Upgrade to swift-nio-ssl version 2.37.2 or later, where this vulnerability is addressed. No other mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apple
- Date Reserved
- 2026-05-01T22:46:27.822Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a622e759c2644c7f84289a4
Added to database: 07/23/2026, 15:08:37 UTC
Last enriched: 07/23/2026, 15:22:19 UTC
Last updated: 07/23/2026, 15:48:45 UTC
Views: 8
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