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TI-2026-31909 Aliases CVE-2026-43820

Out-of-bounds read in Apple swift-nio-ssl

Priority HIGH 67CWE-125Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.

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 for such a type can lead to out-of-bounds memory access. This vulnerability is addressed in swift-nio-ssl version 2.37.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00109 1st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed swift-nio-ssl (Apple): 2.37.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Appleswift-nio-sslbefore 2.37.22.37.2Patch availableCNA
  • swift-nio-ssl VendorApple Affected before 2.37.2 Fixed in 2.37.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:apple:swiftnio_ssl:*:*:*:*:*:*:*:*2.18.0 to before 2.37.2VulnerableApple
  • cpe:2.3:a:apple:swiftnio_ssl:*:*:*:*:*:*:*:* Versions 2.18.0 to before 2.37.2 Vulnerable ·Apple

Remediation

  • Fix · CNA swift-nio-ssl (Apple) Fixed in 2.37.2

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat Hardened Images

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43820

References

Exploit 1

  • TI-2019-06407 Apple Swift-Ubuntu: A SwiftNIO application using TLS may be able to execute arbitrary code CVSS 3.1CRITICAL 9.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences