--- id: CVE-2026-42009 title: A flaw was found in gnutls summary: >- 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 cor… severity: high cvss: 7.5 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H' cwe: - CWE-475 vendor: gnu product: gnutls affected: - gnutls - hardened_images - openshift_container_platform = 4.0 - enterprise_linux = 6.0 - enterprise_linux = 7.0 - enterprise_linux = 8.0 - enterprise_linux_for_els = 8.10 - enterprise_linux_for_ibm_z_systems = 8.0_s390x - enterprise_linux_for_ibm_z_systems_els = 8.10 - enterprise_linux_for_power_little_endian = 8.0_ppc64le - enterprise_linux_for_power_little_endian_els = 8.10 - enterprise_linux = 9.0 - enterprise_linux = 9.8 - enterprise_linux_for_els = 9.8 - enterprise_linux_for_eus = 9.8 - enterprise_linux_for_ibm_z_systems = 9.0_s390x - enterprise_linux_for_ibm_z_systems_els = 9.8 - enterprise_linux_for_ibm_z_systems_eus = 9.8 - enterprise_linux_for_power_little_endian = 9.0_ppc64le - enterprise_linux_for_power_little_endian_els = 9.8 - enterprise_linux_for_power_little_endian_eus = 9.8 - enterprise_linux_for_update_services_for_sap_solutions = 9.8 - >- enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions = 9.8 - enterprise_linux = 10.0 - enterprise_linux = 10.2 - enterprise_linux_for_els = 10.2 - enterprise_linux_for_eus = 10.2 - enterprise_linux_for_ibm_z_systems = 10.2 - enterprise_linux_for_ibm_z_systems_els = 10.2 - enterprise_linux_for_ibm_z_systems_eus = 10.2 - enterprise_linux_for_power_little_endian = 10.0 - enterprise_linux_for_power_little_endian = 10.2 - enterprise_linux_for_power_little_endian_els = 10.2 - enterprise_linux_for_power_little_endian_eus = 10.2 published: '2026-05-18' updated: '2026-09-18' sourceUpdated: '2026-09-18T13:18:15.647' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42009' references: - url: 'https://access.redhat.com/errata/RHSA-2026:13274' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:20611' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:20612' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:20613' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:26319' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:26409' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:29197' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:29794' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:30004' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:30849' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:30850' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:32962' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:33125' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:34372' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:34764' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:34788' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:36004' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:36005' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:36006' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:40762' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:41921' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:56786' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:56853' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:56911' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:57483' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:58981' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:59831' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:60019' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:65839' label: secalert@redhat.com - url: 'https://access.redhat.com/security/cve/CVE-2026-42009' label: secalert@redhat.com - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2467279' label: secalert@redhat.com - url: 'https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-2' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:13274' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:20611' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:20612' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:20613' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:26319' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:26409' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:29197' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:29794' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:30004' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:30849' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:30850' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:32962' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:33125' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:34372' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:34764' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:34788' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:36004' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:36005' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:36006' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:40762' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:41921' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:56786' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:56853' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:56911' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:57483' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:58981' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:59831' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:60019' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:65839' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/security/cve/CVE-2026-42009' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2467279' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42009.json label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://www.cve.org/CVERecord?id=CVE-2026-42009' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42009' tags: - nvd - cve.org - csaf - vex - red-hat epss: 0.01335 epssPercentile: 0.69961 ssvc: exploitation: none automatable: 'yes' technicalImpact: partial timestamp: '2026-05-18T19:05:03.965288Z' ingestedAt: '2026-06-26T16:43:13.646Z' patched: - enterprise_linux_server_v_7_els - openshift_container_platform 4.12 - openshift_container_platform 4.13 - openshift_container_platform 4.14 - openshift_container_platform 4.15 - openshift_container_platform 4.16 - openshift_container_platform 4.17 - openshift_container_platform 4.18 - openshift_container_platform 4.19 - openshift_container_platform 4.20 - openshift_container_platform 4.21 - openshift_container_platform 4.22 - enterprise_linux_appstream_eus_v_10_0 - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_8 - enterprise_linux_appstream_aus_v_8_4 - enterprise_linux_appstream_eus_extension_v_8_4 - enterprise_linux_appstream_aus_v_8_6 - enterprise_linux_appstream_eus_extension_v_8_6 - enterprise_linux_appstream_e4s_v_8_8 - enterprise_linux_appstream_tus_v_8_8 - enterprise_linux_appstream_e4s_v_9_2 - enterprise_linux_appstream_e4s_v_9_4 - enterprise_linux_appstream_eus_v_9_6 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_eus_v_10_0 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_aus_v_8_4 - enterprise_linux_baseos_eus_extension_v_8_4 - enterprise_linux_baseos_aus_v_8_6 - enterprise_linux_baseos_eus_extension_v_8_6 - enterprise_linux_baseos_e4s_v_8_8 - enterprise_linux_baseos_tus_v_8_8 - enterprise_linux_baseos_e4s_v_9_2 - enterprise_linux_baseos_e4s_v_9_4 - enterprise_linux_baseos_eus_v_9_6 - enterprise_linux_baseos_v_9 - ai_inference_server 3.2 - discovery 2 --- ## Overview 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. ## Affected - `gnutls` - `hardened_images` - `openshift_container_platform = 4.0` - `enterprise_linux = 6.0` - `enterprise_linux = 7.0` - `enterprise_linux = 8.0` - `enterprise_linux_for_els = 8.10` - `enterprise_linux_for_ibm_z_systems = 8.0_s390x` - `enterprise_linux_for_ibm_z_systems_els = 8.10` - `enterprise_linux_for_power_little_endian = 8.0_ppc64le` - `enterprise_linux_for_power_little_endian_els = 8.10` - `enterprise_linux = 9.0` - `enterprise_linux = 9.8` - `enterprise_linux_for_els = 9.8` - `enterprise_linux_for_eus = 9.8` - `enterprise_linux_for_ibm_z_systems = 9.0_s390x` - `enterprise_linux_for_ibm_z_systems_els = 9.8` - `enterprise_linux_for_ibm_z_systems_eus = 9.8` - `enterprise_linux_for_power_little_endian = 9.0_ppc64le` - `enterprise_linux_for_power_little_endian_els = 9.8` - `enterprise_linux_for_power_little_endian_eus = 9.8` - `enterprise_linux_for_update_services_for_sap_solutions = 9.8` - `enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions = 9.8` - `enterprise_linux = 10.0` - `enterprise_linux = 10.2` - `enterprise_linux_for_els = 10.2` - `enterprise_linux_for_eus = 10.2` - `enterprise_linux_for_ibm_z_systems = 10.2` - `enterprise_linux_for_ibm_z_systems_els = 10.2` - `enterprise_linux_for_ibm_z_systems_eus = 10.2` - `enterprise_linux_for_power_little_endian = 10.0` - `enterprise_linux_for_power_little_endian = 10.2` - `enterprise_linux_for_power_little_endian_els = 10.2` - `enterprise_linux_for_power_little_endian_eus = 10.2` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:34372** · Red Hat · fixed in: Red Hat Enterprise Linux Server (v. 7 ELS) · released 2026-07-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:34372) - **RHSA-2026:59831** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.12 · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:59831) - **RHSA-2026:65839** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.13 · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:65839) - **RHSA-2026:56786** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.14 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:56786) - **RHSA-2026:56911** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.15 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:56911) - **RHSA-2026:56853** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.16 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:56853) - **RHSA-2026:60019** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.17 · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:60019) - **RHSA-2026:57483** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.18 · released 2026-08-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:57483) - **RHSA-2026:40762** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.19 · released 2026-07-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:40762) - **RHSA-2026:34788** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.20 · released 2026-07-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:34788) - **RHSA-2026:34764** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.21 · released 2026-07-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:34764) - **Red Hat VEX** · Important · affected: Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4 · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42009.json)