High severity · published May 26, 2026
CVE-2026-42012
Gnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sans
7.1
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 29% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CM
Cert Manager support for Red Hat OpenShift release 1.17 · Red Hat
All versions, or not specified · source: vendor
CM
Cert Manager support for Red Hat OpenShift release 1.18 · Red Hat
All versions, or not specified · source: vendor
CM
Cert Manager support for Red Hat OpenShift release 1.20 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Discovery 2 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 7 Extended Lifecycle Support · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: vendor
Affected product
CM
Cert Manager support for Red Hat OpenShift release 1.17
Red Hat
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