{"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"}}]}}