{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-39929", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.147Z", "datePublished": "2025-10-04T07:30:55.153Z", "dateUpdated": "2026-08-05T12:06:08.383Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:06:08.383Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix smbdirect_recv_io leak in smbd_negotiate() error path\n\nDuring tests of another unrelated patch I was able to trigger this\nerror: Objects remaining on __kmem_cache_shutdown()" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The affected code is the CIFS client's SMB Direct (RDMA) transport handshake, driven end-to-end by the remote SMB server peer over iWARP/RoCE/InfiniBand; the peer resets the connection and forces the `smbd_reconnect()` → `_smbd_get_connection()` → `smbd_negotiate()` path that leaks. This matches the network-reachable scoring already applied to other client-side smbdirect flaws (CVE-2025-39932, CVE-2025-39933).\nAC:L - The attacker owns both sides of the timing: it initiates the RDMA disconnect that drives the QP toward the error/teardown states in which `ib_post_recv()` fails, and it can force reconnect cycles indefinitely, retrying until it lands in the window between `RDMA_CM_EVENT_ESTABLISHED` and `smbd_post_recv()`. The reporter hit the condition during ordinary testing, and unlimited retries mean no condition is truly outside attacker influence.\nPR:N - The SMB Direct negotiate exchange sits beneath SMB2 NEGOTIATE and SESSION_SETUP, so no credentials, capability, or account on the client is validated anywhere along the path to `smbd_negotiate()`. The remote peer needs no privileges on the target to reset the transport and drive the failing handshake.\nUI:N - Against an already-mounted SMB Direct share — persistent deployment state, not victim participation — the client's demultiplex thread enters `smbd_reconnect()` → `_smbd_get_connection()` → `smbd_negotiate()` automatically whenever the peer drops the connection, with no user action at any point.\nS:U - The leaked `smbdirect_recv_io` object and the un-destroyed per-connection kmem_cache are kernel-internal allocations belonging to the same security authority as the faulting code. No VM, IOMMU, or sandbox boundary is crossed.\nC:N - The orphaned buffer is never freed and never reused, so there is no use-after-free, no out-of-bounds read, and no stale DMA mapping (`sge.length` is 0 on the DMA-error path and already unmapped on the `ib_post_recv` path). Nothing is disclosed to the remote attacker.\nI:N - No memory is corrupted or overwritten — the object simply remains allocated with no dangling reference, so the attacker gains no write primitive and no ability to modify kernel or user data.\nA:H - Every occurrence fires a `slab_bug()` splat plus `WARN()` in `kmem_cache_destroy()`, tainting the kernel and panicking outright on `panic_on_warn=1` systems, and leaves the whole per-connection `smbdirect_recv_io_%p` kmem_cache permanently un-destroyed. Because the remote peer can force unlimited reconnect attempts, the unreclaimable slab caches and their pages accumulate without bound toward memory exhaustion." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/client/smbdirect.c" ], "versions": [ { "version": "f198186aa9bbd60fae7a2061f4feec614d880299", "lessThan": "5aa69aabcb275a8012265233c7694076ce1d9102", "status": "affected", "versionType": "git" }, { "version": "f198186aa9bbd60fae7a2061f4feec614d880299", "lessThan": "aa4cf7615328eae44f3b4bf5f4fde3fb390c27c6", "status": "affected", "versionType": "git" }, { "version": "f198186aa9bbd60fae7a2061f4feec614d880299", "lessThan": "3d7c075c878ac844e33c43e506c2fa27ac7e9689", "status": "affected", "versionType": "git" }, { "version": "f198186aa9bbd60fae7a2061f4feec614d880299", "lessThan": "e7b7a93879558e77d950f1ff9a6f3daa385b33df", "status": "affected", "versionType": "git" }, { "version": "f198186aa9bbd60fae7a2061f4feec614d880299", "lessThan": "922338efaad63cfe30d459dfc59f9d69ff93ded4", "status": "affected", "versionType": "git" }, { "version": "f198186aa9bbd60fae7a2061f4feec614d880299", "lessThan": "0991418bf98f191d0c320bd25245fcffa1998c7e", "status": "affected", "versionType": "git" }, { "version": "f198186aa9bbd60fae7a2061f4feec614d880299", "lessThan": "daac51c7032036a0ca5f1aa419ad1b0471d1c6e0", "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/client/smbdirect.c" ], "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "lessThan": "4.16", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.154", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.108", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.49", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.9", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "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": "4.16", "versionEndExcluding": "5.10.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.1.154" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.6.108" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.12.49" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.16.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5aa69aabcb275a8012265233c7694076ce1d9102" }, { "url": "https://git.kernel.org/stable/c/aa4cf7615328eae44f3b4bf5f4fde3fb390c27c6" }, { "url": "https://git.kernel.org/stable/c/3d7c075c878ac844e33c43e506c2fa27ac7e9689" }, { "url": "https://git.kernel.org/stable/c/e7b7a93879558e77d950f1ff9a6f3daa385b33df" }, { "url": "https://git.kernel.org/stable/c/922338efaad63cfe30d459dfc59f9d69ff93ded4" }, { "url": "https://git.kernel.org/stable/c/0991418bf98f191d0c320bd25245fcffa1998c7e" }, { "url": "https://git.kernel.org/stable/c/daac51c7032036a0ca5f1aa419ad1b0471d1c6e0" } ], "title": "smb: client: fix smbdirect_recv_io leak in smbd_negotiate() error path", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:43:05.033Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html" } ] } ] } }