{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-43185",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-05-01T14:12:55.991Z",
        "datePublished": "2026-05-06T11:27:56.386Z",
        "dateUpdated": "2026-08-05T12:26:23.248Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:26:23.248Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix signededness bug in smb_direct_prepare_negotiation()\n\nsmb_direct_prepare_negotiation() casts an unsigned __u32 value\nfrom sp->max_recv_size and req->preferred_send_size to a signed\nint before computing min_t(int, ...). A maliciously provided\npreferred_send_size of 0x80000000 will return as smaller than\nmax_recv_size, and then be used to set the maximum allowed\nalowed receive size for the next message.\n\nBy sending a second message with a large value (>1420 bytes)\nthe attacker can then achieve a heap buffer overflow.\n\nThis fix replaces min_t(int, ...) with min_t(u32)"
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                        "baseScore": 9.8,
                        "baseSeverity": "CRITICAL"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:N - The vulnerable ksmbd SMB Direct negotiation is reached by a remote peer over the network via the RDMA listener on SMB Direct ports such as 445/5445.\nAC:L - An attacker can trigger the bug with a crafted negotiation request followed by an oversized data-transfer message; no race or victim-controlled timing is required.\nPR:N - The vulnerable path runs during SMB Direct transport negotiation before SMB authentication or session setup, so no credentials or prior privileges are required.\nUI:N - No victim user action is needed beyond the server exposing ksmbd SMB Direct; the attacker sends network protocol messages directly.\nS:U - The impact is kernel memory corruption within the same host security authority, not a cross-scope escape such as guest-to-host or IOMMU boundary bypass.\nC:H - The signedness bug lets the attacker turn a small allocated receive buffer into a huge posted RDMA receive target, causing attacker-controlled kernel heap memory corruption that can plausibly be leveraged for information disclosure.\nI:H - The second SMB Direct message causes an out-of-bounds write/DMA overwrite into kernel heap memory, which is high-integrity impact and plausibly exploitable for control-flow or data corruption.\nA:H - The heap buffer overflow is remotely triggerable pre-authentication and can crash or panic the kernel even without full code execution."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/smb/server/transport_rdma.c"
                    ],
                    "versions": [
                        {
                            "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                            "lessThan": "ceae058eb707ddd0d68f0872f9d9f23b7c30c37b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                            "lessThan": "55abc475d096da4a5356b6efb0cfdc6156bc1550",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                            "lessThan": "6b4f875aac344cdd52a1f34cc70ed2f874a65757",
                            "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/transport_rdma.c"
                    ],
                    "versions": [
                        {
                            "version": "5.15",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.15",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.16",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.19.6",
                            "lessThanOrEqual": "6.19.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.0",
                            "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": "6.18.16"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.15",
                                    "versionEndExcluding": "6.19.6"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.15",
                                    "versionEndExcluding": "7.0"
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            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/ceae058eb707ddd0d68f0872f9d9f23b7c30c37b"
                },
                {
                    "url": "https://git.kernel.org/stable/c/55abc475d096da4a5356b6efb0cfdc6156bc1550"
                },
                {
                    "url": "https://git.kernel.org/stable/c/6b4f875aac344cdd52a1f34cc70ed2f874a65757"
                }
            ],
            "title": "ksmbd: fix signededness bug in smb_direct_prepare_negotiation()",
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}