CVE-2026-42012

What it is

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier (URI) or Service (SRV) Subject Alternative Names (SANs). This could cause the certificate validation process to incorrectly fall back to checking DNS hostnames against the Common Name (CN), potentially allowing the attacker to spoof legitimate services or intercept sensitive information.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of data tampering.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-05-26 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-03 09:17 UTC Last updatedMost recent change to the record

Details

Published

2026-05-26 22:16 UTC

Last modified

2026-11-03 09:17 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-295 · Improper certificate validation

Record status

Awaiting Analysis

Attack profile CVSS 3.1 · 7.1

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

None