{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-55655", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-06-16T23:55:05.737Z", "datePublished": "2026-06-23T03:36:25.724Z", "dateUpdated": "2026-09-01T08:40:48.932Z" }, "containers": { "cna": { "title": "Openssh: local mitm of x11 forwarding via abstract unix socket pre-binding in red hat enterprise linux openssh client versions", "metrics": [ { "other": { "content": { "value": "Moderate", "namespace": "https://access.redhat.com/security/updates/classification/" }, "type": "Red Hat severity rating" } }, { "cvssV3_1": { "attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "NONE", "baseScore": 5, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N", "version": "3.1" }, "format": "CVSS" } ], "descriptions": [ { "lang": "en", "value": "A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session." } ], "affected": [ { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "affected", "versions": [ { "version": "0:9.9p1-25.el10_2", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/o:redhat:enterprise_linux:10.2" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "affected", "versions": [ { "version": "0:8.0p1-30.el8_10", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:enterprise_linux:8::appstream", "cpe:/o:redhat:enterprise_linux:8::baseos" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "affected", "versions": [ { "version": "0:8.0p1-30.el8_10", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:enterprise_linux:8::appstream", "cpe:/o:redhat:enterprise_linux:8::baseos" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "affected", "versions": [ { "version": "0:9.9p1-9.el9_8", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:enterprise_linux:9::appstream", "cpe:/o:redhat:enterprise_linux:9::baseos" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "affected", "versions": [ { "version": "0:9.9p1-9.el9_8", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:enterprise_linux:9::appstream", "cpe:/o:redhat:enterprise_linux:9::baseos" ] }, { "vendor": "Red Hat", "product": "Red Hat Hardened Images", "collectionURL": "https://catalog.redhat.com/software/containers/", "packageName": "openssh-main", "defaultStatus": "affected", "versions": [ { "version": "10.3p1-6.hum1", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:hummingbird:1" ] }, { "vendor": "Red Hat", "product": "Red Hat Update Infrastructure 5", "collectionURL": "https://catalog.redhat.com/software/containers/", "packageName": "rhui5/installer-rhel9", "defaultStatus": "affected", "versions": [ { "version": "1786435483", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:rhui:5::el9" ] }, { "vendor": "Red Hat", "product": "Red Hat Update Infrastructure 5", "collectionURL": "https://catalog.redhat.com/software/containers/", "packageName": "rhui5/rhua-rhel9", "defaultStatus": "affected", "versions": [ { "version": "1786533529", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:rhui:5::el9" ] }, { "vendor": "Red Hat", "product": "Red Hat Update Infrastructure 5", "collectionURL": "https://catalog.redhat.com/software/containers/", "packageName": "rhui5/installer-tp-rhel9", "defaultStatus": "affected", "versions": [ { "version": "1787135742", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:rhui:5::el9" ] }, { "vendor": "Red Hat", "product": "Red Hat Update Infrastructure 5", "collectionURL": "https://catalog.redhat.com/software/containers/", "packageName": "rhui5/rhua-tp-rhel9", "defaultStatus": "affected", "versions": [ { "version": "1787241260", "lessThan": "*", "versionType": "rpm", "status": "unaffected" } ], "cpes": [ "cpe:/a:redhat:rhui:5::el9" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "affected", "cpes": [ "cpe:/o:redhat:enterprise_linux:6" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "affected", "cpes": [ "cpe:/o:redhat:enterprise_linux:7" ] }, { "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openshift/ose-rhel-coreos-8", "defaultStatus": "unknown", "cpes": [ "cpe:/a:redhat:openshift:4" ] }, { "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openshift/ose-rhel-coreos-9", "defaultStatus": "unknown", "cpes": [ "cpe:/a:redhat:openshift:4" ] } ], "references": [ { "url": "https://access.redhat.com/errata/RHSA-2026:36759", "name": "RHSA-2026:36759", "tags": [ "vendor-advisory", "x_refsource_REDHAT" ] }, { "url": "https://access.redhat.com/errata/RHSA-2026:47755", "name": "RHSA-2026:47755", "tags": [ "vendor-advisory", "x_refsource_REDHAT" ] }, { "url": "https://access.redhat.com/errata/RHSA-2026:47756", "name": "RHSA-2026:47756", "tags": [ "vendor-advisory", "x_refsource_REDHAT" ] }, { "url": "https://access.redhat.com/errata/RHSA-2026:47757", "name": "RHSA-2026:47757", "tags": [ "vendor-advisory", "x_refsource_REDHAT" ] }, { "url": "https://access.redhat.com/errata/RHSA-2026:54387", "name": "RHSA-2026:54387", "tags": [ "vendor-advisory", "x_refsource_REDHAT" ] }, { "url": "https://access.redhat.com/errata/RHSA-2026:58981", "name": "RHSA-2026:58981", "tags": [ "vendor-advisory", "x_refsource_REDHAT" ] }, { "url": "https://access.redhat.com/security/cve/CVE-2026-55655", "tags": [ "vdb-entry", "x_refsource_REDHAT" ] }, { "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2462250", "name": "RHBZ#2462250", "tags": [ "issue-tracking", "x_refsource_REDHAT" ] } ], "datePublic": "2026-06-22T23:22:11.127Z", "problemTypes": [ { "descriptions": [ { "cweId": "CWE-923", "description": "Improper Restriction of Communication Channel to Intended Endpoints", "lang": "en", "type": "CWE" } ] } ], "x_redhatCweChain": "CWE-923: Improper Restriction of Communication Channel to Intended Endpoints", "workarounds": [ { "lang": "en", "value": "To mitigate this issue, disable X11 forwarding on OpenSSH clients when it is not required. This can be achieved by avoiding the use of `-X` or `-Y` options when invoking `ssh`, or by setting `ForwardX11 no` in the SSH client configuration file (`~/.ssh/config` or `/etc/ssh/ssh_config`). Disabling X11 forwarding will prevent the client from attempting to establish X11 connections, thereby removing the attack vector." } ], "timeline": [ { "lang": "en", "time": "2026-04-26T18:39:13.000Z", "value": "Reported to Red Hat." }, { "lang": "en", "time": "2026-06-22T23:22:11.127Z", "value": "Made public." } ], "credits": [ { "lang": "en", "value": "This issue was discovered by In partnership with Red Hat (Aisle.com)." } ], "providerMetadata": { "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-09-01T08:40:48.932Z" }, "x_generator": { "engine": "cvelib 1.8.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-23T12:21:42.502865Z", "id": "CVE-2026-55655", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-23T12:21:47.865Z" } } ] } }