{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-74583",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-08-15T05:44:03.918Z",
        "datePublished": "2026-08-21T16:31:55.886Z",
        "dateUpdated": "2026-08-21T16:31:55.886Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-21T16:31:55.886Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_route: fix fastmap use-after-free on filter\n\nThe route4 classifier maintains a 16-slot fastmap cache that stores raw\nstruct route4_filter pointers indexed by (id, iif). The reader\n(route4_classify) populates this cache via route4_set_fastmap() for every\nclassified packet that hits a filter. The writer (route4_delete,\nroute4_change) clears the cache via route4_reset_fastmap() before\nRCU-deferred kfree of the filter.\n\nThis creates a UAF race:\n 1. Reader walks the RCU-protected bucket chain, finds filter f\n 2. Writer unlinks f, calls route4_reset_fastmap(), then tcf_queue_work()\n 3. Reader calls route4_set_fastmap() and writes f into the cache\n    *after* the writer's reset, caching a pointer about to be freed\n 4. After the RCU grace period, kfree(f) executes\n 5. Next classified packet on the same (id, iif) tuple hits the stale\n    fastmap entry and reads f->res from freed memory\n\nReproduced with an mdelay(100) accelerator in route4_set_fastmap() and a\nconcurrent add/delete stress test (provided by both zdi and Santosh).\nBoth triggered KASAN slab-use-after-free reports in the route4 fastmap\npaths.\n\nFix:\nIntroduce a per-filter boolean dying flag to suppress stale fastmap\nrepublishing by in-flight readers."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/sched/cls_route.c"
                    ],
                    "versions": [
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                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "7897198b26445b4009a057bda1986b94a99e5d5f",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "820f083c294ad6d319c02a7d43294f2ed2565139",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "5ec9001be6d0eb527251125632ec8fe88278897f",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "b969984b2bdc85d721ce4047cd270cd37ec705a2",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "a17f636c9330eac879822ce29f998e5abd1b72c1",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "0e7a8cf8895b06d07c7311f028eba16ad742b9bc",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "ae9aff87025219005a2d16b4fe83d6f24643e50d",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1109c00547fc66df45b9ff923544be4c1e1bec13",
                            "lessThan": "47d7f7051253bdc02b1d245d87e38f16d31a74df",
                            "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/sched/cls_route.c"
                    ],
                    "versions": [
                        {
                            "version": "3.18",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "3.18",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.265",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.216",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.183",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.152",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.104",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.45",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1.9",
                            "lessThanOrEqual": "7.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
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                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.18",
                                    "versionEndExcluding": "5.10.265"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.18",
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            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/7897198b26445b4009a057bda1986b94a99e5d5f"
                },
                {
                    "url": "https://git.kernel.org/stable/c/820f083c294ad6d319c02a7d43294f2ed2565139"
                },
                {
                    "url": "https://git.kernel.org/stable/c/5ec9001be6d0eb527251125632ec8fe88278897f"
                },
                {
                    "url": "https://git.kernel.org/stable/c/b969984b2bdc85d721ce4047cd270cd37ec705a2"
                },
                {
                    "url": "https://git.kernel.org/stable/c/a17f636c9330eac879822ce29f998e5abd1b72c1"
                },
                {
                    "url": "https://git.kernel.org/stable/c/0e7a8cf8895b06d07c7311f028eba16ad742b9bc"
                },
                {
                    "url": "https://git.kernel.org/stable/c/ae9aff87025219005a2d16b4fe83d6f24643e50d"
                },
                {
                    "url": "https://git.kernel.org/stable/c/47d7f7051253bdc02b1d245d87e38f16d31a74df"
                }
            ],
            "title": "net/sched: cls_route: fix fastmap use-after-free on filter",
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}