{"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":"2026-08-21T12:01:41.901Z"},"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 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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/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":"2026-08-21T12:01:41.901Z"},"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"}}]}}