{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-31437",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-03-09T15:48:24.090Z",
        "datePublished": "2026-04-22T13:53:36.361Z",
        "dateUpdated": "2026-05-11T22:08:41.432Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-05-11T22:08:41.432Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry\n\nWhen a write subrequest is marked NETFS_SREQ_NEED_RETRY, the retry path\nin netfs_unbuffered_write() unconditionally calls stream->prepare_write()\nwithout checking if it is NULL.\n\nFilesystems such as 9P do not set the prepare_write operation, so\nstream->prepare_write remains NULL. When get_user_pages() fails with\n-EFAULT and the subrequest is flagged for retry, this results in a NULL\npointer dereference at fs/netfs/direct_write.c:189.\n\nFix this by mirroring the pattern already used in write_retry.c: if\nstream->prepare_write is NULL, skip renegotiation and directly reissue\nthe subrequest via netfs_reissue_write(), which handles iterator reset,\nIN_PROGRESS flag, stats update and reissue internally."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/netfs/direct_write.c"
                    ],
                    "versions": [
                        {
                            "version": "72d08d2839649d1c5efbe375751f4473fa4486af",
                            "lessThan": "a4d1b4ba9754bac3efebd06f583a44a7af52c0ab",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "0c29f6d63122a0168d67cb8ecde5b4cf7fe4acb0",
                            "lessThan": "7a5482f5ce891decbf36f2e6fab1e9fc4a76a684",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "a0b4c7a49137ed21279f354eb59f49ddae8dffc2",
                            "lessThan": "e9075e420a1eb3b52c60f3b95893a55e77419ce8",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/netfs/direct_write.c"
                    ],
                    "versions": [
                        {
                            "version": "6.18.17",
                            "lessThan": "6.18.21",
                            "status": "affected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.19.7",
                            "lessThan": "6.19.11",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.18.17",
                                    "versionEndExcluding": "6.18.21"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.19.7",
                                    "versionEndExcluding": "6.19.11"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/a4d1b4ba9754bac3efebd06f583a44a7af52c0ab"
                },
                {
                    "url": "https://git.kernel.org/stable/c/7a5482f5ce891decbf36f2e6fab1e9fc4a76a684"
                },
                {
                    "url": "https://git.kernel.org/stable/c/e9075e420a1eb3b52c60f3b95893a55e77419ce8"
                }
            ],
            "title": "netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}