{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-98084",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-25T10:19:56.075Z",
        "datePublished": "2026-09-25T10:24:19.881Z",
        "dateUpdated": "2026-10-21T12:54:25.939Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-21T12:54:25.939Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: backtracking shouldn't clear outer frame R1-R5 for callbacks\n\nWhen processing calls to bpf_loop() verifier marks R1 (and R4) as\nprecise. R1 tracks loop iterations number and because of the\n'callback_depth < R1' mechanics in check_helper_call() must be marked\nprecise. However, precision propagation for R1 was broken,\nwhen bpf_loop() call was verified on a second iteration.\n\nConsider the following verification trace:\n- main: bpf_loop(nr_loops, callback ...)\n- callback: BPF_EXIT\n- main: bpf_loop(nr_loops, callback ...)\n- ...\n\nWhile the first visit of the call to bpf_loop() propagated R1\nprecision as expected, the second call to mark_chain_precision() in\nthe check_helper_call() set R1, but it was immediately reset when\nbacktrack_insn() processed preceding BPF_EXIT in the loop deleted in\nthis patch.\n\nBecause of that, the second visit of the call to bpf_loop() injected\ncheckpoint with R1 not marked as precise. Which could trick the\nverifier into accepting unsafe programs. See the next patch for an\nexample of such program.\n\nCommit is structured in a way to minimize conflicts when\n'bpf' would be eventually merged with 'bpf-next'."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "kernel/bpf/backtrack.c"
                    ],
                    "versions": [
                        {
                            "version": "b43550d7d58e7ae6618aaab18c1e912fa4d6e3dd",
                            "lessThan": "1ac58dab0a83d2c64e3b807a3a0b399f17a74110",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "ab5cfac139ab8576fb54630d4cca23c3e690ee90",
                            "lessThan": "cdc93c6370f792d0649df2a145ac0cdcd430e411",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "ab5cfac139ab8576fb54630d4cca23c3e690ee90",
                            "lessThan": "3a39bc9707fbd1bef4df7318a9d02222741dda5b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "ab5cfac139ab8576fb54630d4cca23c3e690ee90",
                            "lessThan": "f83890dfed9efc5e19df1dbc1ad707a142936923",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "ab5cfac139ab8576fb54630d4cca23c3e690ee90",
                            "lessThan": "e3e4f66cc4b72333d0886ae2673c360248987889",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "6.6.15",
                            "lessThan": "6.6.160",
                            "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/bpf/backtrack.c"
                    ],
                    "versions": [
                        {
                            "version": "6.7",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.7",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.160",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.114",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.57",
                            "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": "6.6.15",
                                    "versionEndExcluding": "6.6.160"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.7",
                                    "versionEndExcluding": "6.12.114"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.7",
                                    "versionEndExcluding": "6.18.57"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.7",
                                    "versionEndExcluding": "7.2.7"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.7",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/1ac58dab0a83d2c64e3b807a3a0b399f17a74110"
                },
                {
                    "url": "https://git.kernel.org/stable/c/cdc93c6370f792d0649df2a145ac0cdcd430e411"
                },
                {
                    "url": "https://git.kernel.org/stable/c/3a39bc9707fbd1bef4df7318a9d02222741dda5b"
                },
                {
                    "url": "https://git.kernel.org/stable/c/f83890dfed9efc5e19df1dbc1ad707a142936923"
                },
                {
                    "url": "https://git.kernel.org/stable/c/e3e4f66cc4b72333d0886ae2673c360248987889"
                }
            ],
            "title": "bpf: backtracking shouldn't clear outer frame R1-R5 for callbacks",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}