CVE-2026-43820
Medium
Elevated severity or exploit probability.
CVSS base
7.7
HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS — probability of exploitation (30 days)
0.1%
1.5th percentile
CISA KEV
Not listed
Weakness / dates
CWE-125
Published 2026-07-23 · modified 2026-09-04
CVSS breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
| Attack Vector | L | Local |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | N | None |
| Availability | H | High |
Timeline
- 2026-07-23 — Published (NVD)
- 2026-09-04 — Last modified (NVD)
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.