# CVE-2026-3833

## Summary

- **CVE ID:** CVE-2026-3833
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
- **CWE:** CWE-178
- **Published:** Apr 30, 2026
- **Last Modified:** Sep 17, 2026

## Description

A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.

## Affected Products

- Red Hat — Red Hat Hardened Images (3.8.13-1.hum1)
- Unknown product (0)
- Red Hat — Red Hat Enterprise Linux 8 (0:3.6.16-8.el8_10.6)
- Red Hat — Red Hat Enterprise Linux 10 (0:3.8.10-4.el10_2)
- Red Hat — Red Hat Enterprise Linux 9 (0:3.8.10-4.el9_8)
- Red Hat — Red Hat Enterprise Linux 10.0 Extended Update Support (0:3.8.9-9.el10_0.19)
- Red Hat — Red Hat Update Infrastructure 5 (1781525684)
- Red Hat — Red Hat Update Infrastructure 5 (1781525671)
- Red Hat — Red Hat Update Infrastructure 5 (1781525693)
- Red Hat — Red Hat Update Infrastructure 5 (1781525739)
- Red Hat — Red Hat Discovery 2 (1782159791)
- Red Hat — Red Hat Discovery 2 (1782166952)
- Red Hat — Red Hat Enterprise Linux 9.6 Extended Update Support (0:3.8.3-6.el9_6.4)
- Red Hat — Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (0:3.6.14-10.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (0:4.13-3.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (0:3.6.14-10.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (0:4.13-3.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (0:3.6.16-5.el8_6.5)
- Red Hat — Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (0:4.13-3.el8_6.2)
- Red Hat — Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (0:3.6.16-5.el8_6.5)
- Red Hat — Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (0:4.13-3.el8_6.2)
- Red Hat — Red Hat Enterprise Linux 8.8 Telecommunications Update Service (0:3.6.16-7.el8_8.4)
- Red Hat — Red Hat Enterprise Linux 8.8 Telecommunications Update Service (0:4.13-4.el8_8.1)
- Red Hat — Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (0:3.6.16-7.el8_8.4)
- Red Hat — Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (0:4.13-4.el8_8.1)
- Red Hat — Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions (0:3.8.3-4.el9_4.6)
- Red Hat — Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (0:3.7.6-21.el9_2.7)
- Red Hat — Red Hat Enterprise Linux 7 Extended Lifecycle Support (0:3.3.29-9.el7_9.2)
- Red Hat — Red Hat Update Infrastructure 5 (1787241211)
- Red Hat — Red Hat Update Infrastructure 5 (1787135742)
- Red Hat — Red Hat Update Infrastructure 5 (1787241260)
- Red Hat — Red Hat OpenShift Container Platform 4.19 (4.19.9.6.202608182320-0)
- Red Hat — Red Hat OpenShift Container Platform 4.12 (412.86.202608241157-0)
- Red Hat — Red Hat OpenShift Container Platform 4.17 (417.94.202608250221-0)
- Red Hat — Red Hat OpenShift Container Platform 4.16 (416.94.202609011112-0)
- Red Hat — Red Hat OpenShift Container Platform 4.14 (414.92.202609011250-0)
- Red Hat — Red Hat OpenShift Container Platform 4.18 (418.94.202609031320-0)
- Red Hat — Red Hat OpenShift Container Platform 4.13 (413.92.202609080414-0)

## References

- [CNA](https://access.redhat.com/security/cve/CVE-2026-3833)
- [CNA](https://bugzilla.redhat.com/show_bug.cgi?id=2445763)
- [CNA](https://gitlab.com/gnutls/gnutls/-/issues/1803)
- [CNA](https://access.redhat.com/errata/RHSA-2026:13274)
- [CNA](https://access.redhat.com/errata/RHSA-2026:20611)
- [CNA](https://access.redhat.com/errata/RHSA-2026:20613)
- [CNA](https://access.redhat.com/errata/RHSA-2026:20612)
- [CNA](https://access.redhat.com/errata/RHSA-2026:26319)
- [CNA](https://access.redhat.com/errata/RHSA-2026:26409)
- [CNA](https://access.redhat.com/errata/RHSA-2026:29197)
- [CNA](https://access.redhat.com/errata/RHSA-2026:30004)
- [CNA](https://access.redhat.com/errata/RHSA-2026:30849)
- [CNA](https://access.redhat.com/errata/RHSA-2026:30850)
- [CNA](https://access.redhat.com/errata/RHSA-2026:32962)
- [CNA](https://access.redhat.com/errata/RHSA-2026:33125)
- [CNA](https://access.redhat.com/errata/RHSA-2026:41921)
- [CNA](https://access.redhat.com/errata/RHSA-2026:43575)
- [CNA](https://access.redhat.com/errata/RHSA-2026:58981)
- [CNA](https://access.redhat.com/errata/RHSA-2026:57402)
- [CNA](https://access.redhat.com/errata/RHSA-2026:59831)
- [CNA](https://access.redhat.com/errata/RHSA-2026:60019)
- [CNA](https://access.redhat.com/errata/RHSA-2026:62549)
- [CNA](https://access.redhat.com/errata/RHSA-2026:62409)
- [CNA](https://access.redhat.com/errata/RHSA-2026:65851)
- [CNA](https://access.redhat.com/errata/RHSA-2026:65839)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.56%
- **EPSS Percentile:** 45.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._