CVE-2025-37899

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The handler for that connection could\nbe in the smb2_sess_setup function which makes use of sess->user."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - ksmbd is the in-kernel SMB server; both the freeing SMB2 LOGOFF and the racing SMB2 SESSION_SETUP (multichannel bind) are ordinary SMB PDUs delivered over TCP/445 from a remote client. No local access is required.\nAC:L - The attacker controls both sides of the race \u2014 they open both TCP connections and choose when to send LOGOFF and the binding SESSION_SETUP \u2014 and both paths block on slow ksmbd.mountd IPC round trips (`ksmbd_ipc_login_request()` / `ksmbd_ipc_logout_request()`), giving a very wide window that can be retried indefinitely with fresh sessions.\nPR:L - `smb2_session_logoff()` is gated by `ksmbd_conn_good()` and a successful `ksmbd_session_lookup_all()`, and channel binding requires a non-guest session, so the attacker needs one ordinary unprivileged SMB account (any share user, no admin rights) \u2014 matching the kernel CNA scoring of the sibling multichannel session UAFs CVE-2025-22040/22041.\nUI:N - The attacker drives both connections and both SMB requests entirely on their own; no action by any local user or administrator is needed.\nS:U - The corruption stays within the kernel's own memory and security authority \u2014 a standard in-kernel use-after-free with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The freed `struct ksmbd_user` holds `name`, `passkey` and `passkey_sz`; after reclaim, `ksmbd_compare_user()` performs a `memcmp` of attacker-chosen length through a dangling pointer (unbounded OOB read usable as an oracle) and `smb2_query_info` FS_OBJECTID copies 16 bytes via `user_passkey(sess->user)` straight into the network response, disclosing kernel memory and the victim's NTLM passkey to the remote client.\nI:H - `set_user_flag(sess->user, KSMBD_USER_FLAG_BAD_PASSWORD)` performs an OR-write into the freed object, and `sess->user->uid`/`->gid` from freed memory drive `smb_inherit_dacl()` and file ownership; combined with heap spraying of the reclaimed slab object this yields a write primitive suitable for control-flow hijack.\nA:H - Dereferencing the freed `ksmbd_user` (and the `sess->user = NULL` store racing other readers) reliably produces kernel oopses, slab corruption, or a panic, taking down the file server."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/smb2pdu.c"], "versions": [{"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "931dc8a3670f71c45c0b1379ea4e92dafbda1aca", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "70ad6455139e26e85f48f95d0e21f351c1909342", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "d5ec1d79509b3ee01de02c236f096bc050221b7f", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "02d16046cd11a5c037b28c12ffb818c56dd3ef43", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "2fc9feff45d92a92cd5f96487655d5be23fb7e2b", "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/smb/server/smb2pdu.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.159", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.119", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.28", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.14.6", "lessThanOrEqual": "6.14.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.15", "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": "5.15", "versionEndExcluding": "6.1.159"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.119"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.28"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.14.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.15"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/931dc8a3670f71c45c0b1379ea4e92dafbda1aca"}, {"url": "https://git.kernel.org/stable/c/70ad6455139e26e85f48f95d0e21f351c1909342"}, {"url": "https://git.kernel.org/stable/c/d5ec1d79509b3ee01de02c236f096bc050221b7f"}, {"url": "https://git.kernel.org/stable/c/02d16046cd11a5c037b28c12ffb818c56dd3ef43"}, {"url": "https://git.kernel.org/stable/c/2fc9feff45d92a92cd5f96487655d5be23fb7e2b"}], "title": "ksmbd: fix use-after-free in session logoff", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-05-24T19:05:08.356Z"}, "references": [{"url": "https://sean.heelan.io/2025/05/22/how-i-used-o3-to-find-cve-2025-37899-a-remote-zeroday-vulnerability-in-the-linux-kernels-smb-implementation/"}, {"url": "https://news.ycombinator.com/item?id=44081338"}], "title": "CVE Program Container", "x_generator": {"engine": "ADPogram 0.0.1"}}]}}

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The handler for that connection could\nbe in the smb2_sess_setup function which makes use of sess->user."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ksmbd: correcci\u00f3n del problema \"use-after-free\" al cerrar sesi\u00f3n. El objeto sess->user puede estar siendo utilizado por otro hilo, por ejemplo, si otra conexi\u00f3n ha enviado una solicitud de configuraci\u00f3n de sesi\u00f3n para enlazarse a la sesi\u00f3n que se est\u00e1 liberando. El controlador de esa conexi\u00f3n podr\u00eda estar en la funci\u00f3n smb2_sess_setup, que utiliza sess->user."}], "id": "CVE-2025-37899", "lastModified": "2026-07-30T06:22:30.547", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"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": "nvd@nist.gov", "type": "Primary"}]}, "published": "2025-05-20T16:15:26.273", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/02d16046cd11a5c037b28c12ffb818c56dd3ef43"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/2fc9feff45d92a92cd5f96487655d5be23fb7e2b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/70ad6455139e26e85f48f95d0e21f351c1909342"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/931dc8a3670f71c45c0b1379ea4e92dafbda1aca"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/d5ec1d79509b3ee01de02c236f096bc050221b7f"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Exploit", "Issue Tracking", "Third Party Advisory"], "url": "https://news.ycombinator.com/item?id=44081338"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Exploit", "Third Party Advisory"], "url": "https://sean.heelan.io/2025/05/22/how-i-used-o3-to-find-cve-2025-37899-a-remote-zeroday-vulnerability-in-the-linux-kernels-smb-implementation/"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: ksmbd: fix use-after-free in session logoff", "id": "2367544", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2367544"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-416", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nksmbd: fix use-after-free in session logoff\nThe sess->user object can currently be in use by another thread, for\nexample if another connection has sent a session setup request to\nbind to the session being free'd. The handler for that connection could\nbe in the smb2_sess_setup function which makes use of sess->user."], "name": "CVE-2025-37899", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "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": "2025-05-20T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-37899\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-37899\nhttps://lore.kernel.org/linux-cve-announce/2025052055-CVE-2025-37899-7366@gregkh/T"], "threat_severity": "Low"}

{"created": "2025-06-27T09:26:51.881335+00:00", "updated": "2025-06-27T09:26:51.881418+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}