{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38437", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.016Z", "datePublished": "2025-07-25T15:27:16.995Z", "dateUpdated": "2026-08-05T12:01:53.911Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:01:53.911Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix potential use-after-free in oplock/lease 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." } ], "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 - The vulnerable code is the ksmbd in-kernel SMB server's SMB2_OPLOCK_BREAK handler (fs/smb/server/smb2pdu.c), reached directly from an SMB2 PDU received on TCP/445. No local access is required.\nAC:L - The attacker fully controls both sides of the sequence — granting the oplock/lease, triggering the break from a second connection, and sending the ack — 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 — file open, conflicting open to force the break, and the oplock/lease break ack — 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" } } ] } }