{"id":"CVE-2026-55653","title":"A flaw was found in OpenSSH","summary":"A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group va…","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L","cwe":["CWE-415"],"vendor":"openbsd","product":"openssh","affected":["openssh","hardened_images","openshift_container_platform = 4.0","enterprise_linux = 6.0","enterprise_linux = 7.0","enterprise_linux = 8.0","enterprise_linux = 9.0","enterprise_linux = 10.0"],"patched":["enterprise_linux_appstream_eus_v_10_0","enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_8","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_e4s_v_9_4","enterprise_linux_baseos_v_9","hardened_images","update_infrastructure 5"],"published":"2026-06-23","updated":"2026-10-14","sourceUpdated":"2026-10-14T20:17:49.213","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55653","references":[{"url":"https://access.redhat.com/errata/RHSA-2026:36759","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:47755","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:47756","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:47757","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:54387","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:58981","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:76748","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:76993","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:80513","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82749","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82750","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82751","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82752","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82753","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82754","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82755","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82756","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82757","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82758","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82759","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82761","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82762","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82763","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82897","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82898","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82899","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82900","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82901","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82902","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82903","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82904","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82907","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82908","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82909","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82910","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82912","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82913","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82914","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82915","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82916","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82917","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82918","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82920","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82921","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82922","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:82923","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/security/cve/CVE-2026-55653","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2462351","label":"secalert@redhat.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55653.json"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-55653"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55653"},{"url":"https://access.redhat.com/errata/RHSA-2026:89739","label":"RHSA-2026:89739"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.0053,"epssPercentile":0.44594,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-06-23T14:30:51.025049Z"},"ingestedAt":"2026-08-24T13:03:31.720Z","slug":"CVE-2026-55653","body":"## Overview\n\nA flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).\n\n## Affected\n\n- `openssh`\n- `hardened_images`\n- `openshift_container_platform = 4.0`\n- `enterprise_linux = 6.0`\n- `enterprise_linux = 7.0`\n- `enterprise_linux = 8.0`\n- `enterprise_linux = 9.0`\n- `enterprise_linux = 10.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:76748** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · released 2026-10-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:76748)\n- **RHSA-2026:47757** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-07-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:47757)\n- **RHSA-2026:47755** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-07-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:47755)\n- **RHSA-2026:47756** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-07-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:47756)\n- **RHSA-2026:76993** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS E4S (v.9.4) · released 2026-10-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:76993)\n- **RHSA-2026:36759** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:36759)\n- **RHSA-2026:54387** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-08-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:54387)\n- **RHSA-2026:58981** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-08-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:58981)\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55653.json)\n- **RHSA-2026:80513** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6) · released 2026-10-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:80513)\n- **RHSA-2026:82749** · Red Hat · fixed in: Red Hat OpenShift AI 3.4 · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:82749)\n- **RHSA-2026:89739** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89739)\n- **RHSA-2026:82761** · Red Hat · fixed in: Red Hat OpenShift AI 3.0 · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:82761)\n- **RHSA-2026:82751** · Red Hat · fixed in: Red Hat OpenShift AI 3.0 · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:82751)\n- **RHSA-2026:82914** · Red Hat · fixed in: Red Hat OpenShift AI 3.0 · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:82914)","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}