CVE-2026-42009
Gnutls: gnutls: denial of service via dtls packet reordering vulnerability
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.
| CWE | CWE-475 |
| Vendor | red hat |
| Product | red hat enterprise linux 10 |
| Published | May 18, 2026 |
| Last Updated | Jul 2, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Red Hat / Red Hat Enterprise Linux 10
All versions affected Red Hat / Red Hat Enterprise Linux 10.0 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
All versions affected Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
All versions affected Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
All versions affected Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
All versions affected Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service
All versions affected Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service
All versions affected Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
All versions affected Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected Red Hat / Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
All versions affected Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.22
All versions affected Red Hat / Red Hat Discovery 2
All versions affected Red Hat / Red Hat Discovery 2
All versions affected Red Hat / Red Hat Hardened Images
All versions affected Red Hat / Red Hat Update Infrastructure 5
All versions affected Red Hat / Red Hat Update Infrastructure 5
All versions affected Red Hat / Red Hat Update Infrastructure 5
All versions affected Red Hat / Red Hat Update Infrastructure 5
All versions affected Red Hat / Red Hat Enterprise Linux 6
All versions affected References
access.redhat.com: https://access.redhat.com/errata/RHSA-2026:13274 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:20611 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:20612 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:20613 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:26319 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:26409 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:29197 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:29794 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:30004 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:30849 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:30850 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:32962 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33125 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:34372 access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-42009 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2467279 gnutls.org: https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-2 security.access.redhat.com: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42009.json
Credits
Red Hat would like to thank Joshua Rogers (AISLE Research Team) for reporting this issue.