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        "cveId": "CVE-2026-78409",
        "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "state": "PUBLISHED",
        "assignerShortName": "redhat",
        "dateReserved": "2026-08-24T14:40:18.012Z",
        "datePublished": "2026-09-02T15:11:47.184Z",
        "dateUpdated": "2026-09-02T15:53:16.424Z"
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    "containers": {
        "cna": {
            "title": "Util-linux: util-linux: x-mount.subdir detached-tree resolution can escape via intermediate symlinks",
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                            "value": "Important",
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                        "type": "Red Hat severity rating"
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                    "cvssV3_1": {
                        "attackComplexity": "HIGH",
                        "attackVector": "LOCAL",
                        "availabilityImpact": "HIGH",
                        "baseScore": 7,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "HIGH",
                        "integrityImpact": "HIGH",
                        "privilegesRequired": "LOW",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
                        "version": "3.1"
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            "descriptions": [
                {
                    "lang": "en",
                    "value": "The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to open_tree() with AT_SYMLINK_NOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with an fstab-authorized X-mount.subdir entry can attach a host path at the intended mountpoint."
                }
            ],
            "affected": [
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                    "product": "Red Hat Enterprise Linux 10",
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                    "packageName": "util-linux",
                    "defaultStatus": "unaffected",
                    "cpes": [
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                    "product": "Red Hat Enterprise Linux 7",
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                    "product": "Red Hat Enterprise Linux 8",
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                    "product": "Red Hat Enterprise Linux 9",
                    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                    "packageName": "rhel8/flatpak-runtime",
                    "defaultStatus": "unaffected",
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                    "packageName": "rhel8/flatpak-sdk",
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                    "product": "Red Hat OpenShift Container Platform 4",
                    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                    "packageName": "rhcos",
                    "defaultStatus": "unaffected",
                    "cpes": [
                        "cpe:/a:redhat:openshift:4"
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            ],
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                {
                    "url": "https://access.redhat.com/security/cve/CVE-2026-78409",
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                    "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2522607",
                    "name": "RHBZ#2522607",
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                {
                    "url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-8f2p-47x3-43mv"
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            "datePublic": "2026-09-02T00:00:00.000Z",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-59",
                            "description": "Improper Link Resolution Before File Access ('Link Following')",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "x_redhatCweChain": "CWE-59: Improper Link Resolution Before File Access ('Link Following')",
            "workarounds": [
                {
                    "lang": "en",
                    "value": "Upgrade to util-linux v2.41.6, v2.42.3, or later. Until a fix is applied, do not allow unprivileged /etc/fstab entries that specify X-mount.subdir."
                }
            ],
            "timeline": [
                {
                    "lang": "en",
                    "time": "2026-06-17T00:00:00.000Z",
                    "value": "Reported to Red Hat."
                },
                {
                    "lang": "en",
                    "time": "2026-09-02T00:00:00.000Z",
                    "value": "Made public."
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "Upstream acknowledges Zhuorao Yang (Huawei Cloud) as the original reporter."
                }
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                        "url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-8f2p-47x3-43mv",
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                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-09-02T15:29:06.011028Z",
                                "id": "CVE-2026-78409",
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                                        "Exploitation": "poc"
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                                        "Automatable": "no"
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                                        "Technical Impact": "total"
                                    }
                                ],
                                "role": "CISA Coordinator",
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                "title": "CISA ADP Vulnrichment",
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