{
    "document": {
        "category": "csaf_base",
        "csaf_version": "2.0",
        "distribution": {
            "tlp": {
                "label": "WHITE"
            }
        },
        "lang": "en",
        "notes": [
            {
                "category": "legal_disclaimer",
                "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings."
            }
        ],
        "publisher": {
            "category": "coordinator",
            "contact_details": "cert@ncsc.nl",
            "name": "National Cyber Security Centre",
            "namespace": "https://www.ncsc.nl/"
        },
        "title": "CVE-2026-31402",
        "tracking": {
            "current_release_date": "2026-04-03T16:53:46.326458Z",
            "generator": {
                "date": "2026-02-17T15:00:00Z",
                "engine": {
                    "name": "V.E.L.M.A",
                    "version": "1.7"
                }
            },
            "id": "CVE-2026-31402",
            "initial_release_date": "2026-04-03T15:39:35.507771Z",
            "revision_history": [
                {
                    "date": "2026-04-03T15:39:35.507771Z",
                    "number": "1",
                    "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| Products created (6).| Products connected (8).| References created (6)."
                },
                {
                    "date": "2026-04-03T15:39:45.279318Z",
                    "number": "2",
                    "summary": "NCSC Score created."
                },
                {
                    "date": "2026-04-03T16:50:42.581389Z",
                    "number": "3",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| References created (6)."
                }
            ],
            "status": "interim",
            "version": "3"
        }
    },
    "product_tree": {
        "branches": [
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "category": "product_version_range",
                                "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<0f0e2a54a31a7f9ad2915db99156114872317388",
                                "product": {
                                    "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<0f0e2a54a31a7f9ad2915db99156114872317388",
                                    "product_id": "CSAFPID-5992248"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<5133b61aaf437e5f25b1b396b14242a6bb0508e2",
                                "product": {
                                    "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<5133b61aaf437e5f25b1b396b14242a6bb0508e2",
                                    "product_id": "CSAFPID-5992250"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<8afb437ea1f70cacb4bbdf11771fb5c4d720b965",
                                "product": {
                                    "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<8afb437ea1f70cacb4bbdf11771fb5c4d720b965",
                                    "product_id": "CSAFPID-5992246"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<ae8498337dfdfda71bdd0b807c9a23a126011d76",
                                "product": {
                                    "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<ae8498337dfdfda71bdd0b807c9a23a126011d76",
                                    "product_id": "CSAFPID-5992249"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<c9452c0797c95cf2378170df96cf4f4b3bca7eff",
                                "product": {
                                    "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<c9452c0797c95cf2378170df96cf4f4b3bca7eff",
                                    "product_id": "CSAFPID-5992245"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<dad0c3c0a8e5d1d6eb0fc455694ce3e25e6c57d0",
                                "product": {
                                    "name": "vers:git/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2|<dad0c3c0a8e5d1d6eb0fc455694ce3e25e6c57d0",
                                    "product_id": "CSAFPID-5992247"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:semver/6.1.167|<=6.1.*",
                                "product": {
                                    "name": "vers:semver/6.1.167|<=6.1.*",
                                    "product_id": "CSAFPID-5904654"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:semver/6.12.78|<=6.12.*",
                                "product": {
                                    "name": "vers:semver/6.12.78|<=6.12.*",
                                    "product_id": "CSAFPID-5904671"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:semver/6.18.20|<=6.18.*",
                                "product": {
                                    "name": "vers:semver/6.18.20|<=6.18.*",
                                    "product_id": "CSAFPID-5905005"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:semver/6.19.10|<=6.19.*",
                                "product": {
                                    "name": "vers:semver/6.19.10|<=6.19.*",
                                    "product_id": "CSAFPID-5905006"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:semver/6.6.130|<=6.6.*",
                                "product": {
                                    "name": "vers:semver/6.6.130|<=6.6.*",
                                    "product_id": "CSAFPID-5904647"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:semver/<2.6.12",
                                "product": {
                                    "name": "vers:semver/<2.6.12",
                                    "product_id": "CSAFPID-1286808"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/2.6.12",
                                "product": {
                                    "name": "vers:unknown/2.6.12",
                                    "product_id": "CSAFPID-1286807"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/7.0-rc5|<=*",
                                "product": {
                                    "name": "vers:unknown/7.0-rc5|<=*",
                                    "product_id": "CSAFPID-5905027"
                                }
                            }
                        ],
                        "category": "product_name",
                        "name": "Linux"
                    }
                ],
                "category": "vendor",
                "name": "Linux"
            }
        ]
    },
    "vulnerabilities": [
        {
            "cve": "CVE-2026-31402",
            "notes": [
                {
                    "category": "description",
                    "text": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix heap overflow in NFSv4.0 LOCK replay cache\n\nThe NFSv4.0 replay cache uses a fixed 112-byte inline buffer\n(rp_ibuf[NFSD4_REPLAY_ISIZE]) to store encoded operation responses.\nThis size was calculated based on OPEN responses and does not account\nfor LOCK denied responses, which include the conflicting lock owner as\na variable-length field up to 1024 bytes (NFS4_OPAQUE_LIMIT).\n\nWhen a LOCK operation is denied due to a conflict with an existing lock\nthat has a large owner, nfsd4_encode_operation() copies the full encoded\nresponse into the undersized replay buffer via read_bytes_from_xdr_buf()\nwith no bounds check. This results in a slab-out-of-bounds write of up\nto 944 bytes past the end of the buffer, corrupting adjacent heap memory.\n\nThis can be triggered remotely by an unauthenticated attacker with two\ncooperating NFSv4.0 clients: one sets a lock with a large owner string,\nthen the other requests a conflicting lock to provoke the denial.\n\nWe could fix this by increasing NFSD4_REPLAY_ISIZE to allow for a full\nopaque, but that would increase the size of every stateowner, when most\nlockowners are not that large.\n\nInstead, fix this by checking the encoded response length against\nNFSD4_REPLAY_ISIZE before copying into the replay buffer. If the\nresponse is too large, set rp_buflen to 0 to skip caching the replay\npayload. The status is still cached, and the client already received the\ncorrect response on the original request.",
                    "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/31xxx/CVE-2026-31402.json"
                },
                {
                    "category": "description",
                    "text": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix heap overflow in NFSv4.0 LOCK replay cache\n\nThe NFSv4.0 replay cache uses a fixed 112-byte inline buffer\n(rp_ibuf[NFSD4_REPLAY_ISIZE]) to store encoded operation responses.\nThis size was calculated based on OPEN responses and does not account\nfor LOCK denied responses, which include the conflicting lock owner as\na variable-length field up to 1024 bytes (NFS4_OPAQUE_LIMIT).\n\nWhen a LOCK operation is denied due to a conflict with an existing lock\nthat has a large owner, nfsd4_encode_operation() copies the full encoded\nresponse into the undersized replay buffer via read_bytes_from_xdr_buf()\nwith no bounds check. This results in a slab-out-of-bounds write of up\nto 944 bytes past the end of the buffer, corrupting adjacent heap memory.\n\nThis can be triggered remotely by an unauthenticated attacker with two\ncooperating NFSv4.0 clients: one sets a lock with a large owner string,\nthen the other requests a conflicting lock to provoke the denial.\n\nWe could fix this by increasing NFSD4_REPLAY_ISIZE to allow for a full\nopaque, but that would increase the size of every stateowner, when most\nlockowners are not that large.\n\nInstead, fix this by checking the encoded response length against\nNFSD4_REPLAY_ISIZE before copying into the replay buffer. If the\nresponse is too large, set rp_buflen to 0 to skip caching the replay\npayload. The status is still cached, and the client already received the\ncorrect response on the original request.",
                    "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-31402"
                },
                {
                    "category": "other",
                    "text": "4.1",
                    "title": "NCSC Score"
                },
                {
                    "category": "other",
                    "text": "The value of the most recent CVSS (V3) score, Is related to a product by vendor Linux",
                    "title": "NCSC Score top decreasing factors"
                }
            ],
            "product_status": {
                "known_affected": [
                    "CSAFPID-1286807",
                    "CSAFPID-5992245",
                    "CSAFPID-5992246",
                    "CSAFPID-5992247",
                    "CSAFPID-5992248",
                    "CSAFPID-5992249",
                    "CSAFPID-5992250"
                ],
                "known_not_affected": [
                    "CSAFPID-1286808",
                    "CSAFPID-5904647",
                    "CSAFPID-5904654",
                    "CSAFPID-5904671",
                    "CSAFPID-5905005",
                    "CSAFPID-5905006",
                    "CSAFPID-5905027"
                ]
            },
            "references": [
                {
                    "category": "external",
                    "summary": "Source - cveprojectv5",
                    "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/31xxx/CVE-2026-31402.json"
                },
                {
                    "category": "external",
                    "summary": "Source - nvd",
                    "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-31402"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://git.kernel.org/stable/c/c9452c0797c95cf2378170df96cf4f4b3bca7eff"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://git.kernel.org/stable/c/8afb437ea1f70cacb4bbdf11771fb5c4d720b965"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://git.kernel.org/stable/c/dad0c3c0a8e5d1d6eb0fc455694ce3e25e6c57d0"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://git.kernel.org/stable/c/0f0e2a54a31a7f9ad2915db99156114872317388"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://git.kernel.org/stable/c/ae8498337dfdfda71bdd0b807c9a23a126011d76"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://git.kernel.org/stable/c/5133b61aaf437e5f25b1b396b14242a6bb0508e2"
                }
            ],
            "title": "CVE-2026-31402"
        }
    ]
}