{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-98284",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-25T10:25:14.335Z",
        "datePublished": "2026-10-06T08:45:45.443Z",
        "dateUpdated": "2026-10-19T09:16:55.695Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-19T09:16:55.695Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetlink: do not free nlk->groups while lockless readers can use it\n\nnetlink_realloc_groups() uses krealloc() under netlink_table_grab().\nWhenever NLGRPSZ(groups) lands in a different kmalloc bucket, the old\nbitmap is freed immediately.\n\nTwo readers of nlk->groups / nlk->ngroups do not hold the netlink\ntable lock:\n\n1) sk_diag_dump_groups(). Hashed (bound) sockets are dumped from the\n   rhashtable walk in __netlink_diag_dump(), which only holds RCU.\n   Only the mc_list part of the dump takes nl_table_lock.\n\n2) netlink_native_seq_show() (/proc/net/netlink), whose walk has been\n   lockless since commit 21e4902aea80 (\"netlink: Lockless lookup with\n   RCU grace period in socket release\").\n\nBoth can read a freed buffer, and sk_diag_dump_groups() can also read\npast the end of the old (smaller) buffer if it happens to load the old\n@groups pointer together with the new @ngroups value, copying the\nresult into a NETLINK_DIAG_GROUPS attribute.\n\nThis is the same class of bug that commit f773608026ee (\"netlink:\naccess nlk groups safely in netlink bind and getname\") fixed for bind()\nand getname(); these two readers were missed. Simply grabbing the table\nlock in sk_diag_dump_groups() is not an option, because it is also\ncalled with nl_table_lock already held from the mc_list section of the\ndump.\n\nMake the lockless readers safe instead:\n\n- Allocate a new bitmap and free the old one after an RCU grace period,\n  instead of relying on the implicit kfree() done by krealloc().\n\n- Publish @groups before @ngroups, both with release semantics, and have\n  the lockless readers load @ngroups first. A reader can then never pair\n  the new (bigger) size with the old (smaller) buffer, and a reader\n  picking up the new pointer while still seeing the old size is\n  guaranteed to see the initialized bitmap.\n\nnetlink_realloc_groups() is called from process context (bind() and\nsetsockopt()), so kfree_rcu_mightsleep() can be used, once the table\nhas been released."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/netlink/af_netlink.c",
                        "net/netlink/diag.c"
                    ],
                    "versions": [
                        {
                            "version": "21e4902aea80ef35afc00ee8d2abdea4f519b7f7",
                            "lessThan": "22f313e211d58a66786c81487c3905fa5d4b2a8f",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "21e4902aea80ef35afc00ee8d2abdea4f519b7f7",
                            "lessThan": "ceac0de741bfb47ca255eee075257b3bb31f0651",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/netlink/af_netlink.c",
                        "net/netlink/diag.c"
                    ],
                    "versions": [
                        {
                            "version": "4.0",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.0",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.8",
                            "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": "4.0",
                                    "versionEndExcluding": "7.2.8"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.0",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/22f313e211d58a66786c81487c3905fa5d4b2a8f"
                },
                {
                    "url": "https://git.kernel.org/stable/c/ceac0de741bfb47ca255eee075257b3bb31f0651"
                }
            ],
            "title": "netlink: do not free nlk->groups while lockless readers can use it",
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                "engine": "bippy-1.2.0"
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    }
}