{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-98861",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-25T10:25:14.376Z",
        "datePublished": "2026-10-18T15:51:22.271Z",
        "dateUpdated": "2026-10-19T09:26:55.805Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-19T09:26:55.805Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching()\n\nunregister_fprobe() and unregister_fprobe_async() (used by BPF\nkprobe-multi) rely on standard RCU grace periods (synchronize_rcu()\nand call_rcu()) to wait until in-flight fprobe handlers complete before\nfreeing the fprobe.\n\nHowever, if an fprobe handler executes while RCU is not watching (such\nas in the idle loop or nohz_full extended quiescent states), standard\nRCU does not track preemption-disabled sections. Consequently,\nsynchronize_rcu() does not wait for those executions, which can lead\nto a use-after-free if the fprobe is freed immediately after\nunregistration. Ensure handlers exit early when !rcu_is_watching().\n\nFurthermore, fprobe_fgraph_entry() and fprobe_ftrace_entry() previously\nused guard(rcu)() and rcu_read_lock(), which invoke lockdep on every\nhit under CONFIG_PROVE_LOCKING. This adds overhead and can cause lockdep\nrecursion if probed functions interact with lockdep.\n\nSince rhltable_lookup() and rhl_for_each_entry_rcu() use\nrcu_dereference_all_check() (which checks rcu_read_lock_any_held()),\nholding preemption disabled via rcu_read_lock_sched_notrace() is fully\nvalid and sufficient so long as rcu_is_watching() is true.\n\nDefine and use guard(rcu_sched_notrace)() across fprobe_ftrace_entry(),\nfprobe_fgraph_entry(), and fprobe_return(). This eliminates fast-path\nrcu_read_lock() and lockdep overhead while guaranteeing safe grace\nperiod synchronization."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "kernel/trace/fprobe.c"
                    ],
                    "versions": [
                        {
                            "version": "56b4cfcf1518245493c60fd39c56978f508f1816",
                            "lessThan": "a85d0f00671b4d4527317c10ba018680f7d8d673",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "657b594b2084b39a4bc6d8493aa2140cb00cea49",
                            "lessThan": "dd4a0d4993633b45470abf6da4ea0ca563402245",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "657b594b2084b39a4bc6d8493aa2140cb00cea49",
                            "lessThan": "e0a6249190402a28f1e2925a81acf573157d55ef",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "a4f6a9005ed6cfd360ef2520430927f05f92ffb0",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "6.18.34",
                            "lessThan": "6.18.56",
                            "status": "affected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.0.11",
                            "lessThan": "7.1",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "kernel/trace/fprobe.c"
                    ],
                    "versions": [
                        {
                            "version": "7.1",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "7.1",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.56",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.10",
                            "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": "6.18.34",
                                    "versionEndExcluding": "6.18.56"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "7.1",
                                    "versionEndExcluding": "7.2.10"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "7.1",
                                    "versionEndExcluding": "7.3"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "7.0.11"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/a85d0f00671b4d4527317c10ba018680f7d8d673"
                },
                {
                    "url": "https://git.kernel.org/stable/c/dd4a0d4993633b45470abf6da4ea0ca563402245"
                },
                {
                    "url": "https://git.kernel.org/stable/c/e0a6249190402a28f1e2925a81acf573157d55ef"
                }
            ],
            "title": "fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching()",
            "x_generator": {
                "engine": "bippy-1.2.0"
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        }
    }
}