{"id":"CVE-2026-53264","revision":null,"records":[{"revision":"fff56e495db5423e9579fa7e76df5145","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-53264","aliases":[],"title":"net/sched: act_api: use RCU with deferred freeing for action lifecycle","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_api: use RCU with deferred freeing for action lifecycle\n\nWhen NEWTFILTER and DELFILTER are run concurrently it is possible to create a\nrace with an associated action.\n\nLet's illustrate with CPU0 running NEWTFILTER and CPU1 running DELFILTER:\n\n 0: mutex_lock() <-- holds the idr lock\n 0: rcu_read_lock()\n 0: p = idr_find(idr, index) <-- action p is valid (RCU protects IDR)\n 0: mutex_unlock() <-- releases the idr lock\n 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held\n 1: idr_remove(idr, index) <-- Action removed from IDR\n 1: mutex_unlock() <-- mutex released allowing us to delete the action\n 1: tcf_action_cleanup(p); kfree(p) <-- Kfrees p immediately, no deferral\n 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- ouch, UAF p points to freed memory\n\nThis patch fixes the race condition between NEWTFILTER and DELFILTER by\nadding struct rcu_head to tc_action used in the deferral and introducing a\ncall_rcu() in the delete path to defer the final kfree().\n\nNote: this is a revert of commit d7fb60b9cafb (\"net_sched: get rid of tcfa_rcu\")\nbut also modernization/simplification to directly use kfree_rcu().\n\nLet's illustrate the new restored code path:\n\n 0: rcu_read_lock()\n 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held\n 1: idr_remove(idr, index)\n 1: mutex_unlock()\n 1: call_rcu(&p->tcfa_rcu, tcf_action_rcu_free) <-- defer kfree after grace period\n 0: p = idr_find(idr, index)\n 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- fails, refcnt already 0\n 1: rcu_read_unlock() <-- release so freeing can run after grace period\n\nAfter CPU1 calls idr_remove(), the object is no longer reachable through the IDR.\nCPU0's subsequent idr_find() will return NULL, and even if it still held a\nstale pointer, the immediate kfree() is now deferred until after the RCU grace\nperiod, so no UAF can occur.","state":0,"publishedAt":"2026-06-25T08:39:51.87+00:00","modifiedAt":"2026-10-15T01:23:06.219+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/act_api.h\",\n                        \"net/sched/act_api.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"98b2e40879abf0245be5a5b7af69e0f6ff524ac3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"18af5d2ef0c4f65787fd1280c8b23286b9f2a835\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"1f1b98fea6b9ea30507d0f2fbff6750292d097e2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"8b136f18ac4b2ace5aaad3305b3f8a5d8165a009\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"5dd51e09020c65aa53cf128e5e3517cd53b3c113\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"b60e9391142e983fab2be53497aa8f71fdd09cd5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"91d105d2cbe002f9c7b43a6183adedc37e1da1f7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da\",\n                            \"lessThan\": \"5057e1aca011e51ef51498c940ef96f3d3e8a305\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/act_api.h\",\n                        \"net/sched/act_api.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.259\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.210\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.176\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.143\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.94\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.36\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.13\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/98b2e40879abf0245be5a5b7af69e0f6ff524ac3","https://git.kernel.org/stable/c/18af5d2ef0c4f65787fd1280c8b23286b9f2a835","https://git.kernel.org/stable/c/1f1b98fea6b9ea30507d0f2fbff6750292d097e2","https://git.kernel.org/stable/c/8b136f18ac4b2ace5aaad3305b3f8a5d8165a009","https://git.kernel.org/stable/c/5dd51e09020c65aa53cf128e5e3517cd53b3c113","https://git.kernel.org/stable/c/b60e9391142e983fab2be53497aa8f71fdd09cd5","https://git.kernel.org/stable/c/91d105d2cbe002f9c7b43a6183adedc37e1da1f7","https://git.kernel.org/stable/c/5057e1aca011e51ef51498c940ef96f3d3e8a305"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-53264","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-53264","identifiers":["CVE-2026-53264"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-83353c603c8b44ff880a9955a737c288","complete":false,"records":13655,"lastAttemptAt":"2026-11-09T18:17:25.0500848+00:00","lastSuccessAt":"2026-11-09T18:17:25.037+00:00","error":"6 identifier lookups failed; latest failures include HTTP 403. Other identifiers were checked independently.","lastVerifiedAt":"2026-11-09T18:17:25.037+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13294,"expectedIdentifiers":13707,"failedIdentifiers":6},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-09T18:04:49.9033842+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-09T18:04:49.9033842+00:00","lastSuccessAt":"2026-11-09T18:04:51.425345+00:00","error":null,"lastVerifiedAt":"2026-11-09T18:04:51.425345+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-b51e790980dd40318db1b79f996a5e64","complete":true,"records":13667,"lastAttemptAt":"2026-11-09T18:05:17.6533401+00:00","lastSuccessAt":"2026-11-09T18:05:17.648+00:00","error":null,"lastVerifiedAt":"2026-11-09T18:05:17.648+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13707,"expectedIdentifiers":13707,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-09T18:04:49.7604938+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-09T18:04:49.7604938+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-712163772d637a9cfaa34d4241efb9e9d0ccd6149596c672c613d362f44af841","complete":true,"records":1971,"lastAttemptAt":"2026-11-09T18:02:23.1622896+00:00","lastSuccessAt":"2026-11-09T18:02:23.0088273+00:00","error":null,"lastVerifiedAt":"2026-11-09T18:02:23.1622896+00:00","snapshotPublishedAt":"2026-11-09T17:03:01+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-761ecc9061239b0da572dc9254c6f384c1d19339eb08408c436647a2f26129e9","complete":true,"records":3064,"lastAttemptAt":"2026-11-09T18:04:49.8693187+00:00","lastSuccessAt":"2026-11-09T17:05:03.4044794+00:00","error":null,"lastVerifiedAt":"2026-11-09T18:04:49.8693187+00:00","snapshotPublishedAt":"2026-11-09T16:33:20+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-e3fec63b2a5926ae79916bc9569f5c1069b095db78f2be319f909e69e8e6d7d3","complete":true,"records":231313,"lastAttemptAt":"2026-11-09T18:04:49.6325121+00:00","lastSuccessAt":"2026-11-09T18:04:48.1910635+00:00","error":null,"lastVerifiedAt":"2026-11-09T18:04:49.6325121+00:00","snapshotPublishedAt":"2026-11-09T17:33:10+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}