CVE-2026-43820
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.11%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 7.7 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- EPSS
- 0.11% probability · 1th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-125
- Affected
- apple/swiftnio ssl
- Source
- product-security@apple.com
References
- https://github.com/apple/swift-nio-ssl/security/advisories/GHSA-xfxg-9975-pc2jVendor Advisory, Exploit
- https://github.com/apple/swift-nio-ssl/security/advisories/GHSA-xfxg-9975-pc2jVendor Advisory, Exploit
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.