{"id":"CVE-2026-33846","title":"A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS","summary":"A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type,…","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-130"],"vendor":"Red Hat","product":"gnutls","affected":["gnutls (all versions)","gnutls (all versions)","gnutls (all versions)","gnutls (all versions)","gnutls (all versions)","gnutls (all versions)","libtasn1 (all versions)","gnutls (all versions)","libtasn1 (all versions)","gnutls (all versions)","libtasn1 (all versions)","gnutls (all versions)","libtasn1 (all versions)","gnutls (all versions)","libtasn1 (all versions)","gnutls (all versions)","libtasn1 (all versions)","gnutls (all versions)","gnutls (all versions)","gnutls (all versions)","gnutls (all versions)","gnutls (all versions)","rhcos (all versions)","rhcos (all versions)","rhcos (all versions)","rhcos (all versions)","rhcos (all versions)","rhcos (all versions)","rhcos (all versions)","rhcos (all versions)","rhaiis/model-opt-cuda-rhel9 (all versions)","rhaiis/vllm-cuda-rhel9 (all versions)","rhaiis/vllm-rocm-rhel9 (all versions)","discovery/discovery-server-rhel9 (all versions)","discovery/discovery-ui-rhel9 (all versions)","gnutls-main (all versions)","rhui5/cds-rhel9 (all versions)","rhui5/haproxy-rhel9 (all versions)","rhui5/installer-rhel9 (all versions)","rhui5/rhua-rhel9 (all versions)","rhui5/cds-kubernetes-tp-rhel9 (all versions)","rhui5/installer-tp-rhel9 (all versions)","rhui5/rhua-tp-rhel9 (all versions)","gnutls","openshift4/ose-hypershift-rhel9","openshift/ose-rhel-coreos-8 (all versions)"],"published":"2026-05-04","updated":"2026-09-18","sourceUpdated":"2026-09-18T13:18:03.930","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-33846","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-2026:30004","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-2026:36004","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-2026:41921","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-2026:57402","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-2026-33846","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2450625","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-2026:30004","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-2026:36004","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-2026:41921","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-2026:57402","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:57483","label":"0b0ca135-0b70-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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","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","hardened_images","update_infrastructure 5"],"slug":"CVE-2026-33846","body":"## Overview\n\nA heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type, without validating that the message_length field remains consistent across all fragments of the same logical message. An attacker can exploit this by sending crafted DTLS fragments with conflicting message_length values, causing the implementation to allocate a buffer based on a smaller initial fragment and subsequently write beyond its bounds using larger, inconsistent fragments. Because the merge operation does not enforce proper bounds checking against the allocated buffer size, this results in an out-of-bounds write on the heap. The vulnerability is remotely exploitable without authentication via the DTLS handshake path and can lead to application crashes or potential memory corruption.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **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)\n- **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)\n- **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)\n- **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)\n- **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)\n- **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)\n- **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)\n- **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)\n- **RHSA-2026:57402** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.19 · released 2026-08-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:57402)\n- **RHSA-2026:26409** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · released 2026-06-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:26409)\n- **RHSA-2026:20613** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:20613)\n- **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-2026-33846.json)","depth":"twilight","depthScore":42,"depthScoreParts":{"impact":41.3,"likelihood":0.3,"exploitation":0,"ransomware":0},"changes":[]}