{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-97559",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-24T16:01:01.155Z",
        "datePublished": "2026-09-25T10:21:48.866Z",
        "dateUpdated": "2026-10-21T12:53:17.080Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-21T12:53:17.080Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fail DACL rewrite when the new DACL exceeds 64K\n\nreplace_sids_and_copy_aces() and set_chmod_dacl() accumulate the size of\nthe DACL they build in a u16. That accumulator can wrap.\n\nvalidate_dacl() caps num_aces at (dacl_size - sizeof(struct smb_acl)) /\n20, i.e. 3276 for a maximally sized DACL, while each rewritten ACE can\ngrow to sizeof(struct smb_ace) (76 bytes) once its SID is replaced with\none carrying SID_MAX_SUB_AUTHORITIES sub-authorities. The worst case is\ntherefore sizeof(struct smb_acl) + 3276 * 76 = 248984 bytes, far beyond\nwhat a u16 can hold. A wraparound is reached with 863 ACEs.\n\nAfter the wraparound, ndacl_ptr->size becomes meaningless and the offset\nwill point anywhere in the ACE array. As a result, we will see\ncorruption of the DACL, which then gets sent to the server. This is not\nan out-of-bounds write as the allocation now covers the worst-case\nexpansion, so writes will always go into the buffer.\n\nAdjust the code to use a u32 internally and return -EOVERFLOW in the\noverflow case. The operation must be refused, because a DACL can only\nhold 2^16-1 bytes on the wire and larger DACLs cannot be represented.\n\nset_chmod_dacl() carries the same pattern and is fixed the same way. It\nonly wraps once the source DACL comes within roughly 380 bytes of the\n64K ceiling, but the failure mode is identical."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/smb/client/cifsacl.c"
                    ],
                    "versions": [
                        {
                            "version": "f5065508897a922327f32223082325d10b069ebc",
                            "lessThan": "284877c6189fda1ac3d81771dd8482660a0c7dc1",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f5065508897a922327f32223082325d10b069ebc",
                            "lessThan": "d433376abc47e10870ae732f89c7c1a60b199a0c",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f5065508897a922327f32223082325d10b069ebc",
                            "lessThan": "2ef532a01f44687f5b95001e88247cf05bff9892",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f5065508897a922327f32223082325d10b069ebc",
                            "lessThan": "ee13d687d06a6fbb2008625dd560c654231b28e0",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f5065508897a922327f32223082325d10b069ebc",
                            "lessThan": "d05045177a855386bca5e1909e08d06290e6e3b3",
                            "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/cifsacl.c"
                    ],
                    "versions": [
                        {
                            "version": "5.12",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.12",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.160",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.112",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.53",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.7",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "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": "5.12",
                                    "versionEndExcluding": "6.6.160"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.12",
                                    "versionEndExcluding": "6.12.112"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.12",
                                    "versionEndExcluding": "6.18.53"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.12",
                                    "versionEndExcluding": "7.2.7"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.12",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/284877c6189fda1ac3d81771dd8482660a0c7dc1"
                },
                {
                    "url": "https://git.kernel.org/stable/c/d433376abc47e10870ae732f89c7c1a60b199a0c"
                },
                {
                    "url": "https://git.kernel.org/stable/c/2ef532a01f44687f5b95001e88247cf05bff9892"
                },
                {
                    "url": "https://git.kernel.org/stable/c/ee13d687d06a6fbb2008625dd560c654231b28e0"
                },
                {
                    "url": "https://git.kernel.org/stable/c/d05045177a855386bca5e1909e08d06290e6e3b3"
                }
            ],
            "title": "smb: client: fail DACL rewrite when the new DACL exceeds 64K",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}