CVE-2025-40203

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-40203", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.179Z", "datePublished": "2025-11-12T21:56:34.801Z", "dateUpdated": "2026-08-05T12:08:32.046Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:32.046Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlistmount: don't call path_put() under namespace semaphore\n\nMassage listmount() and make sure we don't call path_put() under the\nnamespace semaphore. If we put the last reference we're fscked."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerability is reached only through the `listmount(2)` system call in fs/namespace.c; there is no remote or adjacent-network path to `do_listmount()`. Exploitation requires the ability to execute syscalls on the target, i.e. local access.\nAC:L - The attacker controls both sides of the race \u2014 it holds the extra path reference via `listmount()` while a `CLONE_FS` sibling thread moves `fs->root` off a lazily-unmounted mount, deterministically making the in-syscall `path_put()` the final reference. The setup (unshare, tmpfs mount, chroot, `umount2(MNT_DETACH)`) is scripted and retryable without limit.\nPR:L - `listmount(2)` requires no capability at all for the caller's own mount namespace, and the mount/chroot/lazy-umount setup is obtainable by any unprivileged user via `unshare -Ur` since CAP_SYS_ADMIN/CAP_SYS_CHROOT are granted inside a user namespace. No real root in the init namespace is needed.\nUI:N - The attacking process performs every step itself \u2014 namespace creation, mount setup, and the concurrent `listmount()`/`chroot()` race. No victim action or cooperation is involved.\nS:U - The corrupted state (`struct mount`, `struct mountpoint`, `struct dentry`, `namespace_sem`) and the resulting impact all live within the kernel's own security authority. No hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - The final `mntput_no_expire()` tears down mounts, frees `struct mountpoint`, and destroys dentries/inodes while only the read side of `namespace_sem` is held, so concurrent readers (other `listmount()`/`statmount()`/propagation walkers that legitimately hold the read lock and expect a stable topology) can traverse freed objects \u2014 a use-after-free giving an attacker-influenceable kernel-memory read primitive via slab reuse.\nI:H - The same violated invariant permits mount-tree list surgery (`list_del(&mnt->mnt_instance)`, `unhash_mnt()`, child reparenting) to race concurrent read-side traversal, yielding linked-list corruption and use-after-free writes into reallocated slab objects, which is exploitable for control-flow hijacking.\nA:H - Performing the final `path_put()` under `namespace_sem` can block or self-deadlock \u2014 inode eviction can stall indefinitely on a userspace filesystem daemon, and `__detach_mounts()`'s `down_write(&namespace_sem)` on an already read-held semaphore deadlocks \u2014 hanging every mount, umount, statmount, and listmount on the system; the same UAF also reliably oopses the kernel."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/namespace.c"], "versions": [{"version": "b4c2bea8ceaa50cd42a8f73667389d801a3ecf2d", "lessThan": "659874b7ee4976ad9ce476e07fd36bc67b3537f1", "status": "affected", "versionType": "git"}, {"version": "b4c2bea8ceaa50cd42a8f73667389d801a3ecf2d", "lessThan": "9c80da26fda2fdcaac7f92b5908875b3108830ff", "status": "affected", "versionType": "git"}, {"version": "b4c2bea8ceaa50cd42a8f73667389d801a3ecf2d", "lessThan": "c1f86d0ac322c7e77f6f8dbd216c65d39358ffc0", "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/namespace.c"], "versions": [{"version": "6.8", "status": "affected"}, {"version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.54", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17.4", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18", "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": "6.8", "versionEndExcluding": "6.12.54"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.17.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/659874b7ee4976ad9ce476e07fd36bc67b3537f1"}, {"url": "https://git.kernel.org/stable/c/9c80da26fda2fdcaac7f92b5908875b3108830ff"}, {"url": "https://git.kernel.org/stable/c/c1f86d0ac322c7e77f6f8dbd216c65d39358ffc0"}], "title": "listmount: don't call path_put() under namespace semaphore", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/namespace.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "659874b7ee4976ad9ce476e07fd36bc67b3537f1", "status": "affected", "version": "b4c2bea8ceaa50cd42a8f73667389d801a3ecf2d", "versionType": "git"}, {"lessThan": "9c80da26fda2fdcaac7f92b5908875b3108830ff", "status": "affected", "version": "b4c2bea8ceaa50cd42a8f73667389d801a3ecf2d", "versionType": "git"}, {"lessThan": "c1f86d0ac322c7e77f6f8dbd216c65d39358ffc0", "status": "affected", "version": "b4c2bea8ceaa50cd42a8f73667389d801a3ecf2d", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/namespace.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.8"}, {"lessThan": "6.8", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.54", "versionType": "semver"}, {"lessThanOrEqual": "6.17.*", "status": "unaffected", "version": "6.17.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.18", "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\nlistmount: don't call path_put() under namespace semaphore\n\nMassage listmount() and make sure we don't call path_put() under the\nnamespace semaphore. If we put the last reference we're fscked."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nlistmount: no llamar a path_put() bajo el sem\u00e1foro del espacio de nombres\n\nAjustar listmount() y asegurarse de que no llamamos a path_put() bajo el sem\u00e1foro del espacio de nombres. Si liberamos la \u00faltima referencia, se producir\u00e1 un fallo cr\u00edtico."}], "id": "CVE-2025-40203", "lastModified": "2026-10-19T21:10:00.160", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2025-11-12T22:15:47.530", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/659874b7ee4976ad9ce476e07fd36bc67b3537f1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9c80da26fda2fdcaac7f92b5908875b3108830ff"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c1f86d0ac322c7e77f6f8dbd216c65d39358ffc0"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Deferred"}

{"bugzilla": {"description": "kernel: listmount: don't call path_put() under namespace semaphore", "id": "2414731", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2414731"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["No description is available for this CVE."], "name": "CVE-2025-40203", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "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": "2025-11-12T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-40203\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-40203\nhttps://lore.kernel.org/linux-cve-announce/2025111247-CVE-2025-40203-c83b@gregkh/T"], "threat_severity": "Moderate"}

{"created": "2025-11-13T09:52:13.798724+00:00", "updated": "2025-11-13T09:52:13.798776+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}