{"id":"CVE-2026-43820","title":"NIOSSLCertificate._subjectAlternativeNames provides access to the raw bytes for a cert's SANs","summary":"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…","severity":"high","cvss":7.7,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","cwe":["CWE-125"],"vendor":"apple","product":"swiftnio_ssl","affected":["swiftnio_ssl >= 2.18.0, < 2.37.2"],"patched":["swiftnio_ssl 2.37.2"],"published":"2026-07-23","updated":"2026-09-04","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-43820","references":[{"url":"https://github.com/apple/swift-nio-ssl/security/advisories/GHSA-xfxg-9975-pc2j","label":"product-security@apple.com"},{"url":"https://github.com/apple/swift-nio-ssl/security/advisories/GHSA-xfxg-9975-pc2j","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd"],"epss":0.0011,"epssPercentile":0.01471,"ingestedAt":"2026-09-05T13:39:55.855Z","slug":"CVE-2026-43820","body":"## Overview\n\nNIOSSLCertificate._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.\n\n## Affected\n\n- `swiftnio_ssl >= 2.18.0, < 2.37.2`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `swiftnio_ssl 2.37.2`","depth":"twilight","depthScore":42,"depthScoreParts":{"impact":42.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}