{"id":"CVE-2026-23074","revision":null,"records":[{"revision":"8373bfe2b9124610bf0e2080845228ad","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-23074","aliases":[],"title":"net/sched: Enforce that teql can only be used as root qdisc","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: Enforce that teql can only be used as root qdisc\n\nDesign intent of teql is that it is only supposed to be used as root qdisc.\nWe need to check for that constraint.\n\nAlthough not important, I will describe the scenario that unearthed this\nissue for the curious.\n\nGangMin Kim <km.kim1503@gmail.com> managed to concot a scenario as follows:\n\nROOT qdisc 1:0 (QFQ)\n  ├── class 1:1 (weight=15, lmax=16384) netem with delay 6.4s\n  └── class 1:2 (weight=1, lmax=1514) teql\n\nGangMin sends a packet which is enqueued to 1:1 (netem).\nAny invocation of dequeue by QFQ from this class will not return a packet\nuntil after 6.4s. In the meantime, a second packet is sent and it lands on\n1:2. teql's enqueue will return success and this will activate class 1:2.\nMain issue is that teql only updates the parent visible qlen (sch->q.qlen)\nat dequeue. Since QFQ will only call dequeue if peek succeeds (and teql's\npeek always returns NULL), dequeue will never be called and thus the qlen\nwill remain as 0. With that in mind, when GangMin updates 1:2's lmax value,\nthe qfq_change_class calls qfq_deact_rm_from_agg. Since the child qdisc's\nqlen was not incremented, qfq fails to deactivate the class, but still\nfrees its pointers from the aggregate. So when the first packet is\nrescheduled after 6.4 seconds (netem's delay), a dangling pointer is\naccessed causing GangMin's causing a UAF.","state":0,"publishedAt":"2026-02-04T16:07:59.379+00:00","modifiedAt":"2026-10-19T18:25:29.342+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                        \"net/sched/sch_teql.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"73d970ff0eddd874a84c953387c7f4464b705fc6\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"ae810e6a8ac4fe25042e6825d2a401207a2e41fb\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"dad49a67c2d817bfec98e6e45121b351e3a0202c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"0686bedfed34155520f3f735cbf3210cb9044380\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"4c7e8aa71c9232cba84c289b4b56cba80b280841\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"16ed73c1282d376b956bff23e5139add061767ba\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"50da4b9d07a7a463e2cfb738f3ad4cff6b2c9c3b\",\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                        \"net/sched/sch_teql.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.12\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.12\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.249\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.199\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.162\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.122\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.68\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.8\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.19\",\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/73d970ff0eddd874a84c953387c7f4464b705fc6","https://git.kernel.org/stable/c/ae810e6a8ac4fe25042e6825d2a401207a2e41fb","https://git.kernel.org/stable/c/dad49a67c2d817bfec98e6e45121b351e3a0202c","https://git.kernel.org/stable/c/0686bedfed34155520f3f735cbf3210cb9044380","https://git.kernel.org/stable/c/4c7e8aa71c9232cba84c289b4b56cba80b280841","https://git.kernel.org/stable/c/16ed73c1282d376b956bff23e5139add061767ba","https://git.kernel.org/stable/c/50da4b9d07a7a463e2cfb738f3ad4cff6b2c9c3b"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-23074","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-23074","identifiers":["CVE-2026-23074"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-08T21:02:31.8931850+00:00","complete":true,"records":1769,"lastAttemptAt":"2026-11-08T21:02:31.893185+00:00","lastSuccessAt":"2026-11-08T21:02:32.2143877+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:32.2146388+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-eaa64dac63caa79c8d4905619258c41c51b39e461b996124e1a21b5e85e7e738-ea572f75aa62c370f36c9951285f437791ed77e310a361fa98b48744b8a4f391","complete":true,"records":421267,"lastAttemptAt":"2026-11-08T21:02:31.4333443+00:00","lastSuccessAt":"2026-11-08T20:47:19.8933196+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:31.4333443+00:00","snapshotPublishedAt":"2026-11-08T20:26:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. 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-45d47722bca14f09ac26662adb699591","complete":true,"records":13654,"lastAttemptAt":"2026-11-08T21:02:36.7086981+00:00","lastSuccessAt":"2026-11-08T20:47:46.939+00:00","error":null,"lastVerifiedAt":"2026-11-08T20:47:46.939+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-08T21:02:31.8931850+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-08T21:02:31.893185+00:00","lastSuccessAt":"2026-11-08T21:02:32.3894193+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:32.38942+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-ddc095a411c54633beb68aaff30b70cb","complete":true,"records":13666,"lastAttemptAt":"2026-11-08T21:02:34.4952279+00:00","lastSuccessAt":"2026-11-08T21:02:34.481+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:34.481+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"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":"2026-11-08T21:02:31.7841816+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:31.7841816+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-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-08T21:02:31.5325642+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:31.5325642+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+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-964c14035e6f0f6478b2870fad6a7ef9f6045876d4a12af2c2e514521e54b6af","complete":true,"records":3055,"lastAttemptAt":"2026-11-08T21:02:31.8040207+00:00","lastSuccessAt":"2026-11-08T11:07:12.1927025+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:31.8040207+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+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-f8647d7ba64b1ba0dfdc7130944766d5b36d5b77d18fff0c79e651a4cff3c2b9","complete":true,"records":231293,"lastAttemptAt":"2026-11-08T21:02:31.6506398+00:00","lastSuccessAt":"2026-11-08T11:06:56.2918717+00:00","error":null,"lastVerifiedAt":"2026-11-08T21:02:31.6506398+00:00","snapshotPublishedAt":"2026-11-08T11:02:50+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}