CVE-2026-74618

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74618", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.921Z", "datePublished": "2026-08-22T15:32:02.778Z", "dateUpdated": "2026-08-22T15:32:02.778Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-22T15:32:02.778Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinfmt_misc: don't warn when the mount is completed from another user namespace\n\nfsopen() records the caller's user namespace in fc->user_ns and hands\nback an ordinary file descriptor. Nothing ties the task that calls\nfsconfig(FSCONFIG_CMD_CREATE) to the task that created the context. The\nfd is inherited across fork() and exec() and it can be passed over a\nunix socket.\n\nCompleting a context from another user namespace is allowed on purpose.\nvfs_cmd_create() authorizes the create with mount_capable(), which for\nFS_USERNS_MOUNT checks ns_capable(fc->user_ns, CAP_SYS_ADMIN), and that\nsucceeds for a task holding CAP_SYS_ADMIN in an ancestor of fc->user_ns.\nSo an unprivileged task can reach the WARN_ON() in bm_fill_super():\ncreate a user and a mount namespace in a child, call\nfsopen(\"binfmt_misc\") there, send the fscontext fd to the parent and let\nthe parent issue FSCONFIG_CMD_CREATE. Both namespaces come from a plain\nunshare(1) and no capability is needed anywhere:\n\n WARNING: fs/binfmt_misc.c:938 at bm_fill_super+0xa2/0xc0 [binfmt_misc]\n CPU: 15 UID: 1000 PID: 3243382 Comm: fswarn\n Call Trace:\n get_tree_keyed+0x7d/0xb0\n bm_get_tree+0x34/0x90 [binfmt_misc]\n vfs_get_tree+0x2a/0x100\n vfs_cmd_create+0x60/0xf0\n __do_sys_fsconfig+0x4b2/0x500\n\nThe child needs the mount namespace because fsopen() itself gates on\nmay_mount(), which asks for CAP_SYS_ADMIN in the user namespace owning\nthe caller's mount namespace. fsconfig() doesn't repeat that check.\n\nIt is a WARN_ON() and not a WARN_ON_ONCE(), so the condition can be\nraised in a loop to taint the kernel and flood the log, and it panics a\nkernel booted with panic_on_warn.\n\nKeep refusing the mount and stop warning about it. Nothing in\nbm_fill_super() depends on the two namespaces matching, it derives\neverything from sb->s_user_ns."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/binfmt_misc.c"], "versions": [{"version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "lessThan": "37cf5cf1320a84a17225a1690547b8a0812ca94e", "status": "affected", "versionType": "git"}, {"version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "lessThan": "24e95a24f151ce40d5fc1b3a6cefbcda8ded736c", "status": "affected", "versionType": "git"}, {"version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "lessThan": "047f927f54c6c17593e93aafe82dcb7acdda2a71", "status": "affected", "versionType": "git"}, {"version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "lessThan": "79fdf39f1a31f88cb3833b6f8091fbf6acdca2c6", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/binfmt_misc.c"], "versions": [{"version": "6.7", "status": "affected"}, {"version": "0", "lessThan": "6.7", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.104", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.104"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.18.45"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.1.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/37cf5cf1320a84a17225a1690547b8a0812ca94e"}, {"url": "https://git.kernel.org/stable/c/24e95a24f151ce40d5fc1b3a6cefbcda8ded736c"}, {"url": "https://git.kernel.org/stable/c/047f927f54c6c17593e93aafe82dcb7acdda2a71"}, {"url": "https://git.kernel.org/stable/c/79fdf39f1a31f88cb3833b6f8091fbf6acdca2c6"}], "title": "binfmt_misc: don't warn when the mount is completed from another user namespace", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/binfmt_misc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "37cf5cf1320a84a17225a1690547b8a0812ca94e", "status": "affected", "version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "versionType": "git"}, {"lessThan": "24e95a24f151ce40d5fc1b3a6cefbcda8ded736c", "status": "affected", "version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "versionType": "git"}, {"lessThan": "047f927f54c6c17593e93aafe82dcb7acdda2a71", "status": "affected", "version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "versionType": "git"}, {"lessThan": "79fdf39f1a31f88cb3833b6f8091fbf6acdca2c6", "status": "affected", "version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/binfmt_misc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.7"}, {"lessThan": "6.7", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.104", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.45", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinfmt_misc: don't warn when the mount is completed from another user namespace\n\nfsopen() records the caller's user namespace in fc->user_ns and hands\nback an ordinary file descriptor. Nothing ties the task that calls\nfsconfig(FSCONFIG_CMD_CREATE) to the task that created the context. The\nfd is inherited across fork() and exec() and it can be passed over a\nunix socket.\n\nCompleting a context from another user namespace is allowed on purpose.\nvfs_cmd_create() authorizes the create with mount_capable(), which for\nFS_USERNS_MOUNT checks ns_capable(fc->user_ns, CAP_SYS_ADMIN), and that\nsucceeds for a task holding CAP_SYS_ADMIN in an ancestor of fc->user_ns.\nSo an unprivileged task can reach the WARN_ON() in bm_fill_super():\ncreate a user and a mount namespace in a child, call\nfsopen(\"binfmt_misc\") there, send the fscontext fd to the parent and let\nthe parent issue FSCONFIG_CMD_CREATE. Both namespaces come from a plain\nunshare(1) and no capability is needed anywhere:\n\n WARNING: fs/binfmt_misc.c:938 at bm_fill_super+0xa2/0xc0 [binfmt_misc]\n CPU: 15 UID: 1000 PID: 3243382 Comm: fswarn\n Call Trace:\n get_tree_keyed+0x7d/0xb0\n bm_get_tree+0x34/0x90 [binfmt_misc]\n vfs_get_tree+0x2a/0x100\n vfs_cmd_create+0x60/0xf0\n __do_sys_fsconfig+0x4b2/0x500\n\nThe child needs the mount namespace because fsopen() itself gates on\nmay_mount(), which asks for CAP_SYS_ADMIN in the user namespace owning\nthe caller's mount namespace. fsconfig() doesn't repeat that check.\n\nIt is a WARN_ON() and not a WARN_ON_ONCE(), so the condition can be\nraised in a loop to taint the kernel and flood the log, and it panics a\nkernel booted with panic_on_warn.\n\nKeep refusing the mount and stop warning about it. Nothing in\nbm_fill_super() depends on the two namespaces matching, it derives\neverything from sb->s_user_ns."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nbinfmt_misc: no advertir cuando el montaje se completa desde otro espacio de nombres de usuario\n\nfsopen() registra el espacio de nombres de usuario del llamador en fc -> user_ns y devuelve un descriptor de archivo ordinario. Nada vincula la tarea que llama a fsconfig(FSCONFIG_CMD_CREATE) con la tarea que cre\u00f3 el contexto. El fd se hereda a trav\u00e9s de fork() y exec() y puede pasarse a trav\u00e9s de un socket unix.\n\nCompletar un contexto desde otro espacio de nombres de usuario est\u00e1 permitido a prop\u00f3sito. vfs_cmd_create() autoriza la creaci\u00f3n con mount_capable(), que para FS_USERNS_MOUNT comprueba ns_capable(fc -> user_ns, CAP_SYS_ADMIN), y eso tiene \u00e9xito para una tarea que posee CAP_SYS_ADMIN en un ancestro de fc -> user_ns. As\u00ed, una tarea sin privilegios puede alcanzar el WARN_ON() en bm_fill_super(): crear un espacio de nombres de usuario y de montaje en un hijo, llamar a fsopen('binfmt_misc') all\u00ed, enviar el fd de fscontext al padre y dejar que el padre emita FSCONFIG_CMD_CREATE. Ambos espacios de nombres provienen de un simple unshare(1) y no se necesita ninguna capacidad en ning\u00fan lugar:\n\n WARNING: fs/binfmt_misc.c:938 at bm_fill_super+0xa2/0xc0 [binfmt_misc]\n CPU: 15 UID: 1000 PID: 3243382 Comm: fswarn\n Ruta de Llamada:\n get_tree_keyed+0x7d/0xb0\n bm_get_tree+0x34/0x90 [binfmt_misc]\n vfs_get_tree+0x2a/0x100\n vfs_cmd_create+0x60/0xf0\n __do_sys_fsconfig+0x4b2/0x500\n\nEl hijo necesita el espacio de nombres de montaje porque fsopen() mismo se basa en may_mount(), que solicita CAP_SYS_ADMIN en el espacio de nombres de usuario propietario del espacio de nombres de montaje del llamador. fsconfig() no repite esa comprobaci\u00f3n.\n\nEs un WARN_ON() y no un WARN_ON_ONCE(), por lo que la condici\u00f3n puede ser elevada en un bucle para corromper el kernel e inundar el registro, y provoca un p\u00e1nico en un kernel arrancado con panic_on_warn.\n\nSeguir rechazando el montaje y dejar de advertir al respecto. Nada en bm_fill_super() depende de que los dos espacios de nombres coincidan, deriva todo de sb -> s_user_ns."}], "id": "CVE-2026-74618", "lastModified": "2026-10-14T13:10:00.187", "metrics": {}, "published": "2026-08-22T16:16:34.507", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/047f927f54c6c17593e93aafe82dcb7acdda2a71"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/24e95a24f151ce40d5fc1b3a6cefbcda8ded736c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/37cf5cf1320a84a17225a1690547b8a0812ca94e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/79fdf39f1a31f88cb3833b6f8091fbf6acdca2c6"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: binfmt_misc: don't warn when the mount is completed from another user namespace", "id": "2521469", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2521469"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-617", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nbinfmt_misc: don't warn when the mount is completed from another user namespace\nfsopen() records the caller's user namespace in fc->user_ns and hands\nback an ordinary file descriptor. Nothing ties the task that calls\nfsconfig(FSCONFIG_CMD_CREATE) to the task that created the context. The\nfd is inherited across fork() and exec() and it can be passed over a\nunix socket.\nCompleting a context from another user namespace is allowed on purpose.\nvfs_cmd_create() authorizes the create with mount_capable(), which for\nFS_USERNS_MOUNT checks ns_capable(fc->user_ns, CAP_SYS_ADMIN), and that\nsucceeds for a task holding CAP_SYS_ADMIN in an ancestor of fc->user_ns.\nSo an unprivileged task can reach the WARN_ON() in bm_fill_super():\ncreate a user and a mount namespace in a child, call\nfsopen(\"binfmt_misc\") there, send the fscontext fd to the parent and let\nthe parent issue FSCONFIG_CMD_CREATE. Both namespaces come from a plain\nunshare(1) and no capability is needed anywhere:\nWARNING: fs/binfmt_misc.c:938 at bm_fill_super+0xa2/0xc0 [binfmt_misc]\nCPU: 15 UID: 1000 PID: 3243382 Comm: fswarn\nCall Trace:\nget_tree_keyed+0x7d/0xb0\nbm_get_tree+0x34/0x90 [binfmt_misc]\nvfs_get_tree+0x2a/0x100\nvfs_cmd_create+0x60/0xf0\n__do_sys_fsconfig+0x4b2/0x500\nThe child needs the mount namespace because fsopen() itself gates on\nmay_mount(), which asks for CAP_SYS_ADMIN in the user namespace owning\nthe caller's mount namespace. fsconfig() doesn't repeat that check.\nIt is a WARN_ON() and not a WARN_ON_ONCE(), so the condition can be\nraised in a loop to taint the kernel and flood the log, and it panics a\nkernel booted with panic_on_warn.\nKeep refusing the mount and stop warning about it. Nothing in\nbm_fill_super() depends on the two namespaces matching, it derives\neverything from sb->s_user_ns.", "A flaw was found in the Linux kernel's `binfmt_misc` component. An unprivileged local user can exploit this vulnerability by manipulating user and mount namespaces to repeatedly trigger a warning condition during the mounting of `binfmt_misc`. This repeated triggering can lead to kernel log flooding, kernel tainting, and potentially a system crash (Denial of Service) if the kernel is configured to panic on warnings."], "name": "CVE-2026-74618", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74618\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74618\nhttps://lore.kernel.org/linux-cve-announce/2026082218-CVE-2026-74618-15d4@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[21ca59b365c091d583f36ac753eaa8baf947be6f,37cf5cf1320a84a17225a1690547b8a0812ca94e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[21ca59b365c091d583f36ac753eaa8baf947be6f,24e95a24f151ce40d5fc1b3a6cefbcda8ded736c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[21ca59b365c091d583f36ac753eaa8baf947be6f,047f927f54c6c17593e93aafe82dcb7acdda2a71)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[21ca59b365c091d583f36ac753eaa8baf947be6f,79fdf39f1a31f88cb3833b6f8091fbf6acdca2c6)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.7"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.7)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.104,7.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.45,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.9,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-22T16:45:03.759625+00:00", "updated": "2026-08-25T16:15:05.599138+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}