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.

CVSS 3.1

7.7CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

EPSS

0.1% chance of exploitation in the next 30 days; higher than 1% of CVEs (scores of 2026-10-25)

CWE

CWE-125

Published

2026-07-23

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

Affected

• apple:swiftnio_ssl

References

• https://github.com/apple/swift-nio-ssl/security/advisories/GHSA-xfxg-9975-pc2j
• https://github.com/apple/swift-nio-ssl/security/advisories/GHSA-xfxg-9975-pc2j

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