CVE-2025-38437

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No local access is required.\nAC:L - The attacker fully controls both sides of the sequence \u2014 granting the oplock/lease, triggering the break from a second connection, and sending the ack \u2014 and can drive the only remaining condition (a `krealloc` failure under `__GFP_RETRY_MAYFAIL`, which fails instead of OOM-killing) by compounding many acks to force repeated iov growth while exhausting kernel memory with concurrent connections and large buffers.\nPR:L - `smb2_check_user_session()` rejects SMB2_OPLOCK_BREAK without a valid session, and the path needs a tree connect plus an open handle holding an oplock or lease, so a basic authenticated share user (or a guest account where the share permits it) is required.\nUI:N - The attacker performs every step \u2014 file open, conflicting open to force the break, and the oplock/lease break ack \u2014 with no action by any legitimate user or administrator.\nS:U - The corruption and its impact are confined to the kernel's own memory and the ksmbd server's security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The refcount underflow frees a still-linked `struct oplock_info` and an extra reference on `struct ksmbd_conn`/`struct ksmbd_file`, so subsequent dereferences of `opinfo->conn`, `->sess`, `->o_fp` and the waitqueue lists read heap the attacker can groom, yielding kernel memory disclosure.\nI:H - The freed object contains two list_heads and two wait_queue_heads still referenced by `fp->f_opinfo`, `ci->m_op_list` and the lease table; reallocating it lets `wake_up_interruptible_all()` invoke an attacker-supplied `wait_queue_entry->func` pointer and lets list unlink act as a write-what-where, giving arbitrary write and code execution.\nA:H - Even without successful exploitation the use-after-free, refcount underflow, and premature `__ksmbd_close_fd()`/connection release reliably produce oops or panic, and the attack can be repeated to keep the server down."}]}], "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": "e38ec88a2b42c494601b1213816d75f0b54d9bf0", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "97c355989928a5f60b228ef5266c1be67a46cdf9", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "815f1161d6dbc4c54ccf94b7d3fdeab34b4d7477", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "8106adc21a2270c16abf69cd74ccd7c79c6e7acd", "status": "affected", "versionType": "git"}, {"version": "0626e6641f6b467447c81dd7678a69c66f7746cf", "lessThan": "50f930db22365738d9387c974416f38a06e8057e", "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": "6.1.146", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.99", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.39", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.15.7", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.16", "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": "6.1.146"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.99"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.39"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.15.7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.16"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/e38ec88a2b42c494601b1213816d75f0b54d9bf0"}, {"url": "https://git.kernel.org/stable/c/97c355989928a5f60b228ef5266c1be67a46cdf9"}, {"url": "https://git.kernel.org/stable/c/815f1161d6dbc4c54ccf94b7d3fdeab34b4d7477"}, {"url": "https://git.kernel.org/stable/c/8106adc21a2270c16abf69cd74ccd7c79c6e7acd"}, {"url": "https://git.kernel.org/stable/c/50f930db22365738d9387c974416f38a06e8057e"}], "title": "ksmbd: fix potential use-after-free in oplock/lease break ack", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:38:00.632Z"}}]}}

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break ack\n\nIf ksmbd_iov_pin_rsp return error, use-after-free can happen by\naccessing opinfo->state and opinfo_put and ksmbd_fd_put could\ncalled twice."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ksmbd: corrige el uso potencial use-after-free en el acuse de recibo de interrupci\u00f3n de oplock/lease Si ksmbd_iov_pin_rsp devuelve un error, el use-after-free puede ocurrir al acceder a opinfo->state y opinfo_put y ksmbd_fd_put podr\u00edan ser llamados dos veces."}], "id": "CVE-2025-38437", "lastModified": "2026-07-30T06:23:14.283", "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"}, 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{"bugzilla": {"description": "kernel: ksmbd: fix potential use-after-free in oplock/lease break ack", "id": "2383518", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2383518"}, "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"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\nksmbd: fix potential use-after-free in oplock/lease break ack\nIf ksmbd_iov_pin_rsp return error, use-after-free can happen by\naccessing opinfo->state and opinfo_put and ksmbd_fd_put could\ncalled twice."], "name": "CVE-2025-38437", "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": "2025-07-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-38437\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-38437\nhttps://lore.kernel.org/linux-cve-announce/2025072559-CVE-2025-38437-9752@gregkh/T"], "threat_severity": "Moderate"}

{"created": "2025-07-26T12:07:40.495356+00:00", "updated": "2025-07-26T12:07:40.495409+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}