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HIGH · 7.7

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...

Vulnerability Description

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.

CVSS Score

7.7

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
HIGH

Related Weaknesses (CWE)

CWE-125

References

FAQ

What is CVE-2026-43820?

CVE-2026-43820 is a vulnerability with a CVSS score of 7.7 (HIGH). 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...

How severe is CVE-2026-43820?

CVE-2026-43820 has been rated HIGH with a CVSS base score of 7.7/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-43820?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.