Gnutls: gnutls: certificate validation bypass due to oversized subject alternative name
Affects the gnutls library and many Red Hat products, including RHEL 9 and OpenShift. No vendor rating is given; CVSS is 8.2 (high). Fixed in gnutls-3.8.10-4.el9_8.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Fix
- Fixed in gnutls-3.8.10-4.el9_8
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name (SAN) could cause the validation process to incorrectly fall back to checking the Common Name (CN) field. This could allow a remote attacker to bypass proper certificate validation, potentially leading to spoofing or man-in-the-middle attacks.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- gnutls
0
- gnutls
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- gnutls
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- gnutls
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- gnutls
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- gnutls
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- libtasn1
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- gnutls
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- libtasn1
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- gnutls
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- libtasn1
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- gnutls
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- libtasn1
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- gnutls
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- libtasn1
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- gnutls
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- libtasn1
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- gnutls
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- gnutls
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- gnutls
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- gnutls
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- openshift/ose-rhel-coreos-8
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- openshift/ose-rhel-coreos-9
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- openshift/ose-rhel-coreos-9
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- openshift/ose-rhel-coreos-9
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- openshift/ose-rhel-coreos-9
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- openshift/ose-rhel-coreos-9
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- openshift/ose-rhel-coreos-9
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- openshift/ose-rhel-coreos-9
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- cert-manager/jetstack-cert-manager-acmesolver-rhel9
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- cert-manager/jetstack-cert-manager-rhel9
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- cert-manager/cert-manager-operator-rhel9
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- cert-manager/cert-manager-operator-bundle
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- cert-manager/jetstack-cert-manager-acmesolver-rhel9
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- cert-manager/jetstack-cert-manager-rhel9
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- cert-manager/cert-manager-istio-csr-rhel9
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- cert-manager/cert-manager-operator-rhel9
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- cert-manager/cert-manager-operator-bundle
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- cert-manager/cert-manager-trust-manager-rhel9
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- discovery/discovery-server-rhel9
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- discovery/discovery-ui-rhel9
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- gnutls-main
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- rhai/base-image-neuron-rhel9
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- rhui5/cds-rhel9
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- rhui5/haproxy-rhel9
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- rhui5/installer-rhel9
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- rhui5/rhua-rhel9
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- rhui5/cds-kubernetes-tp-rhel9
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- rhui5/installer-tp-rhel9
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- rhui5/rhua-tp-rhel9
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- gnutls
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- openshift4/ose-hypershift-rhel9
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- openshift/ose-rhel-coreos-9
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References 25
access.redhat.com
- errata/RHSA-2026:13274
- errata/RHSA-2026:20611
- errata/RHSA-2026:20612
- errata/RHSA-2026:20613
- errata/RHSA-2026:26319
- errata/RHSA-2026:26409
- errata/RHSA-2026:29197
- errata/RHSA-2026:30004
- errata/RHSA-2026:30849
- errata/RHSA-2026:30850
- errata/RHSA-2026:32962
- errata/RHSA-2026:33125
- errata/RHSA-2026:40762
- errata/RHSA-2026:41921
- errata/RHSA-2026:43575
- errata/RHSA-2026:56853
- errata/RHSA-2026:57483
- errata/RHSA-2026:58981
- errata/RHSA-2026:59831
- errata/RHSA-2026:60019
- errata/RHSA-2026:72502
- errata/RHSA-2026:74674
- errata/RHSA-2026:82304
- errata/RHSA-2026:82322
- errata/RHSA-2026:82347
Questions about CVE-2026-42013
What should I do about it?
Update gnutls to gnutls-3.8.10-4.el9_8 or later, the fixed build listed for Red Hat Enterprise Linux 9. No other fixed versions or workaround are listed, so check the vendor advisory for other affected products.Source: access.redhat.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data