CVE-2026-74483

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74483", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.904Z", "datePublished": "2026-08-15T12:27:15.709Z", "dateUpdated": "2026-08-23T12:47:24.496Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-23T12:47:24.496Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinfmt_misc: don't leak the user namespace when the mount fails\n\nbm_get_tree() takes a reference to the user namespace and hands it to\nget_tree_keyed() as the sget key. sget_fc() moves that reference into\nsb->s_fs_info and clears fc->s_fs_info, so from that point on the\nsuperblock owns it and bm_free() doesn't see it anymore.\n\nThe superblock drops it in ->put_super(). But generic_shutdown_super()\nonly calls ->put_super() from inside the if (sb->s_root) branch, so\nnothing releases it when bm_fill_super() fails:\n\n- The kzalloc_obj() failure leaves s_root NULL and the whole branch is\n skipped.\n\n- A simple_fill_super() failure in the file loop leaves s_root set, but\n s_op still points at simple_super_operations, which has no\n ->put_super(). bm_fill_super() installs s_ops only once\n simple_fill_super() returned success, and installing it earlier\n wouldn't help either because simple_fill_super() overwrites s_op.\n\nEither way vfs_get_super() calls deactivate_locked_super() and the\nreference is gone for good. binfmt_misc mounts are available in a user\nnamespace and both the inode and the dentry cache are SLAB_ACCOUNT, so\nan unprivileged caller under a tight memory cgroup can fail\nsimple_fill_super() on demand and leak one user namespace per attempt.\n\nDrop the reference in ->kill_sb() instead, which runs unconditionally,\nthe same way nfsd and rpc_pipefs release their keyed s_fs_info.\n\nThat also stops ->put_super() from clearing s_fs_info while the\nsuperblock is still on @fs_supers. generic_shutdown_super() leaves it\nthere on purpose so that sget_fc() keeps finding it until kill_sb() has\nrun, but a NULL s_fs_info makes test_keyed_super() miss it, so a\nconcurrent mount for the same user namespace skips the grab_super()\nwait and creates a second superblock for a namespace that is still\nbeing torn down."}], "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": "ffec017158d3aad8a6ffca1dfad63d63bde9caad", "status": "affected", "versionType": "git"}, {"version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "lessThan": "867aed6a4848761190d5ebdedf9642648f97bceb", "status": "affected", "versionType": "git"}, {"version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "lessThan": "87a4eb9bbb3497f749bbac612af22ddaa62d7b0d", "status": "affected", "versionType": "git"}, {"version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "lessThan": "b8206f516fe7cbe785cf44bf09c17c438d7c3cad", "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": "6.12.105", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.46", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.8", "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": "6.12.105"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.18.46"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.1.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/ffec017158d3aad8a6ffca1dfad63d63bde9caad"}, {"url": "https://git.kernel.org/stable/c/867aed6a4848761190d5ebdedf9642648f97bceb"}, {"url": "https://git.kernel.org/stable/c/87a4eb9bbb3497f749bbac612af22ddaa62d7b0d"}, {"url": "https://git.kernel.org/stable/c/b8206f516fe7cbe785cf44bf09c17c438d7c3cad"}], "title": "binfmt_misc: don't leak the user namespace when the mount fails", "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": "ffec017158d3aad8a6ffca1dfad63d63bde9caad", "status": "affected", "version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "versionType": "git"}, {"lessThan": "867aed6a4848761190d5ebdedf9642648f97bceb", "status": "affected", "version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "versionType": "git"}, {"lessThan": "87a4eb9bbb3497f749bbac612af22ddaa62d7b0d", "status": "affected", "version": "21ca59b365c091d583f36ac753eaa8baf947be6f", "versionType": "git"}, {"lessThan": "b8206f516fe7cbe785cf44bf09c17c438d7c3cad", "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": "6.12.105", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.46", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.8", "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 leak the user namespace when the mount fails\n\nbm_get_tree() takes a reference to the user namespace and hands it to\nget_tree_keyed() as the sget key. sget_fc() moves that reference into\nsb->s_fs_info and clears fc->s_fs_info, so from that point on the\nsuperblock owns it and bm_free() doesn't see it anymore.\n\nThe superblock drops it in ->put_super(). But generic_shutdown_super()\nonly calls ->put_super() from inside the if (sb->s_root) branch, so\nnothing releases it when bm_fill_super() fails:\n\n- The kzalloc_obj() failure leaves s_root NULL and the whole branch is\n skipped.\n\n- A simple_fill_super() failure in the file loop leaves s_root set, but\n s_op still points at simple_super_operations, which has no\n ->put_super(). bm_fill_super() installs s_ops only once\n simple_fill_super() returned success, and installing it earlier\n wouldn't help either because simple_fill_super() overwrites s_op.\n\nEither way vfs_get_super() calls deactivate_locked_super() and the\nreference is gone for good. binfmt_misc mounts are available in a user\nnamespace and both the inode and the dentry cache are SLAB_ACCOUNT, so\nan unprivileged caller under a tight memory cgroup can fail\nsimple_fill_super() on demand and leak one user namespace per attempt.\n\nDrop the reference in ->kill_sb() instead, which runs unconditionally,\nthe same way nfsd and rpc_pipefs release their keyed s_fs_info.\n\nThat also stops ->put_super() from clearing s_fs_info while the\nsuperblock is still on @fs_supers. generic_shutdown_super() leaves it\nthere on purpose so that sget_fc() keeps finding it until kill_sb() has\nrun, but a NULL s_fs_info makes test_keyed_super() miss it, so a\nconcurrent mount for the same user namespace skips the grab_super()\nwait and creates a second superblock for a namespace that is still\nbeing torn down."}], "id": "CVE-2026-74483", "lastModified": "2026-08-23T13:16:44.530", "metrics": {}, "published": "2026-08-15T13:17:53.163", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/867aed6a4848761190d5ebdedf9642648f97bceb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/87a4eb9bbb3497f749bbac612af22ddaa62d7b0d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b8206f516fe7cbe785cf44bf09c17c438d7c3cad"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ffec017158d3aad8a6ffca1dfad63d63bde9caad"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: binfmt_misc: don't leak the user namespace when the mount fails", "id": "2517022", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2517022"}, "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-911", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nbinfmt_misc: don't leak the user namespace when the mount fails\nbm_get_tree() takes a reference to the user namespace and hands it to\nget_tree_keyed() as the sget key. sget_fc() moves that reference into\nsb->s_fs_info and clears fc->s_fs_info, so from that point on the\nsuperblock owns it and bm_free() doesn't see it anymore.\nThe superblock drops it in ->put_super(). But generic_shutdown_super()\nonly calls ->put_super() from inside the if (sb->s_root) branch, so\nnothing releases it when bm_fill_super() fails:\n- The kzalloc_obj() failure leaves s_root NULL and the whole branch is\nskipped.\n- A simple_fill_super() failure in the file loop leaves s_root set, but\ns_op still points at simple_super_operations, which has no\n->put_super(). bm_fill_super() installs s_ops only once\nsimple_fill_super() returned success, and installing it earlier\nwouldn't help either because simple_fill_super() overwrites s_op.\nEither way vfs_get_super() calls deactivate_locked_super() and the\nreference is gone for good. binfmt_misc mounts are available in a user\nnamespace and both the inode and the dentry cache are SLAB_ACCOUNT, so\nan unprivileged caller under a tight memory cgroup can fail\nsimple_fill_super() on demand and leak one user namespace per attempt.\nDrop the reference in ->kill_sb() instead, which runs unconditionally,\nthe same way nfsd and rpc_pipefs release their keyed s_fs_info.\nThat also stops ->put_super() from clearing s_fs_info while the\nsuperblock is still on @fs_supers. generic_shutdown_super() leaves it\nthere on purpose so that sget_fc() keeps finding it until kill_sb() has\nrun, but a NULL s_fs_info makes test_keyed_super() miss it, so a\nconcurrent mount for the same user namespace skips the grab_super()\nwait and creates a second superblock for a namespace that is still\nbeing torn down.", "A flaw was found in the `binfmt_misc` component of the Linux kernel. An unprivileged local attacker, operating under specific memory constraints (a tight memory cgroup), could repeatedly trigger a failure in the `bm_fill_super()` function during a mount operation. This failure prevents the proper release of a user namespace reference, leading to a leak of one user namespace per attempt. This resource exhaustion can result in a denial of service (DoS) for the system."], "name": "CVE-2026-74483", "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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74483\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74483\nhttps://lore.kernel.org/linux-cve-announce/2026081537-CVE-2026-74483-9915@gregkh/T"], "threat_severity": "Low"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[21ca59b365c091d583f36ac753eaa8baf947be6f,87a4eb9bbb3497f749bbac612af22ddaa62d7b0d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[21ca59b365c091d583f36ac753eaa8baf947be6f,b8206f516fe7cbe785cf44bf09c17c438d7c3cad)"}}], "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": "generic", "value": "6.7"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.7)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.8,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc6,*]"}}], "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": "2026-08-15T14:15:03.646040+00:00", "updated": "2026-08-21T23:00:14.822371+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-911"]}