{"api_version":"1","generated_at":"2026-09-22T03:25:23+00:00","cve":"CVE-2026-90248","urls":{"html":"https://cve.report/CVE-2026-90248","api":"https://cve.report/api/cve/CVE-2026-90248.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-90248","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-90248"},"summary":{"title":"net/sched: cls_api: fix teardown of an adopted proto on insert-race loss","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: fix teardown of an adopted proto on insert-race loss\n\nIn tc_new_tfilter() the create branch sets tp_created = 1 before calling\ntcf_chain_tp_insert_unique(). When the caller loses the race (another\nrequest inserted a proto at the same chain/prio first), insert_unique()\ndestroys the caller's own tp_new and returns the winner's proto with an\nextra reference. tp_created was never cleared, so the loser's errout\npath treated the winner's live proto as its own and called\ntcf_chain_tp_delete_empty() on it, silently unlinking an active\nclassifier that the winning request already advertised via\nRTM_NEWTFILTER.\n\nTrack the outcome of the insert step in a single tri-state variable so\neach errout path reacts correctly:\n\n- TP_NOT_CREATED: no proto created; pursue the old path.\n- TP_CREATED: proto inserted successfully; same code path as before.\n- TP_NOT_OWNED: New - lost the insert race; tp is another request's proto\n  (chain ref already released by tp_new's destroy)\n\nBoth errout reactions are single expressions derived from the state.\n\nThis fix is motivated by the Sashiko's automated review of Patch\n(net/sched: cls_api: Always acquire rtnl_lock when destroying locked\nclassifiers) [1][2]. The review identified the silent-unlink behaviour of\nan adopted proto's teardown when a request loses the\ntcf_chain_tp_insert_unique() race.\n\n[1] https://sashiko.dev/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com\n[2] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-17 17:17:20","updated_at":"2026-09-17 17:17:20"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/d4e359b3608a0e184bbe8d61a5c3b50d0831c44a","name":"https://git.kernel.org/stable/c/d4e359b3608a0e184bbe8d61a5c3b50d0831c44a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dc8b33b819cb02a75936940c120aa669ad89942d","name":"https://git.kernel.org/stable/c/dc8b33b819cb02a75936940c120aa669ad89942d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bbe2fd6d77df630356185406a97317f6aa6a92cf","name":"https://git.kernel.org/stable/c/bbe2fd6d77df630356185406a97317f6aa6a92cf","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bee2208276c8e0e40a249ffdcf6e5434a79a847c","name":"https://git.kernel.org/stable/c/bee2208276c8e0e40a249ffdcf6e5434a79a847c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/219c87aeefdcc8c1caf28cc99e9b361ce7393d3a","name":"https://git.kernel.org/stable/c/219c87aeefdcc8c1caf28cc99e9b361ce7393d3a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/df02b6dc136af45e92ee4c86f4aa6c9a60790b1e","name":"https://git.kernel.org/stable/c/df02b6dc136af45e92ee4c86f4aa6c9a60790b1e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a68e664ddf16ecae6d769d6a2eb356f8abab75c9","name":"https://git.kernel.org/stable/c/a68e664ddf16ecae6d769d6a2eb356f8abab75c9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90248","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90248","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b64678e0af8f4d62a40149baedebe78503a5255 a68e664ddf16ecae6d769d6a2eb356f8abab75c9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b64678e0af8f4d62a40149baedebe78503a5255 df02b6dc136af45e92ee4c86f4aa6c9a60790b1e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b64678e0af8f4d62a40149baedebe78503a5255 bee2208276c8e0e40a249ffdcf6e5434a79a847c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b64678e0af8f4d62a40149baedebe78503a5255 219c87aeefdcc8c1caf28cc99e9b361ce7393d3a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.110 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.52 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.6 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sched/cls_api.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"a68e664ddf16ecae6d769d6a2eb356f8abab75c9","status":"affected","version":"8b64678e0af8f4d62a40149baedebe78503a5255","versionType":"git"},{"lessThan":"df02b6dc136af45e92ee4c86f4aa6c9a60790b1e","status":"affected","version":"8b64678e0af8f4d62a40149baedebe78503a5255","versionType":"git"},{"lessThan":"bee2208276c8e0e40a249ffdcf6e5434a79a847c","status":"affected","version":"8b64678e0af8f4d62a40149baedebe78503a5255","versionType":"git"},{"lessThan":"219c87aeefdcc8c1caf28cc99e9b361ce7393d3a","status":"affected","version":"8b64678e0af8f4d62a40149baedebe78503a5255","versionType":"git"},{"lessThan":"bbe2fd6d77df630356185406a97317f6aa6a92cf","status":"affected","version":"8b64678e0af8f4d62a40149baedebe78503a5255","versionType":"git"},{"lessThan":"dc8b33b819cb02a75936940c120aa669ad89942d","status":"affected","version":"8b64678e0af8f4d62a40149baedebe78503a5255","versionType":"git"},{"lessThan":"d4e359b3608a0e184bbe8d61a5c3b50d0831c44a","status":"affected","version":"8b64678e0af8f4d62a40149baedebe78503a5255","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sched/cls_api.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.1"},{"lessThan":"5.1","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.221","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.188","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.157","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.110","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.52","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.221","versionStartIncluding":"5.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.188","versionStartIncluding":"5.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.157","versionStartIncluding":"5.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.110","versionStartIncluding":"5.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.52","versionStartIncluding":"5.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.6","versionStartIncluding":"5.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"5.1","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: fix teardown of an adopted proto on insert-race loss\n\nIn tc_new_tfilter() the create branch sets tp_created = 1 before calling\ntcf_chain_tp_insert_unique(). When the caller loses the race (another\nrequest inserted a proto at the same chain/prio first), insert_unique()\ndestroys the caller's own tp_new and returns the winner's proto with an\nextra reference. tp_created was never cleared, so the loser's errout\npath treated the winner's live proto as its own and called\ntcf_chain_tp_delete_empty() on it, silently unlinking an active\nclassifier that the winning request already advertised via\nRTM_NEWTFILTER.\n\nTrack the outcome of the insert step in a single tri-state variable so\neach errout path reacts correctly:\n\n- TP_NOT_CREATED: no proto created; pursue the old path.\n- TP_CREATED: proto inserted successfully; same code path as before.\n- TP_NOT_OWNED: New - lost the insert race; tp is another request's proto\n  (chain ref already released by tp_new's destroy)\n\nBoth errout reactions are single expressions derived from the state.\n\nThis fix is motivated by the Sashiko's automated review of Patch\n(net/sched: cls_api: Always acquire rtnl_lock when destroying locked\nclassifiers) [1][2]. The review identified the silent-unlink behaviour of\nan adopted proto's teardown when a request loses the\ntcf_chain_tp_insert_unique() race.\n\n[1] https://sashiko.dev/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com\n[2] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com"}],"providerMetadata":{"dateUpdated":"2026-09-17T16:07:50.104Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/a68e664ddf16ecae6d769d6a2eb356f8abab75c9"},{"url":"https://git.kernel.org/stable/c/df02b6dc136af45e92ee4c86f4aa6c9a60790b1e"},{"url":"https://git.kernel.org/stable/c/bee2208276c8e0e40a249ffdcf6e5434a79a847c"},{"url":"https://git.kernel.org/stable/c/219c87aeefdcc8c1caf28cc99e9b361ce7393d3a"},{"url":"https://git.kernel.org/stable/c/bbe2fd6d77df630356185406a97317f6aa6a92cf"},{"url":"https://git.kernel.org/stable/c/dc8b33b819cb02a75936940c120aa669ad89942d"},{"url":"https://git.kernel.org/stable/c/d4e359b3608a0e184bbe8d61a5c3b50d0831c44a"}],"title":"net/sched: cls_api: fix teardown of an adopted proto on insert-race loss","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-90248","datePublished":"2026-09-17T16:07:50.104Z","dateReserved":"2026-09-11T19:38:34.795Z","dateUpdated":"2026-09-17T16:07:50.104Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-17 17:17:20","lastModifiedDate":"2026-09-17 17:17:20","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"90248","Ordinal":"1","Title":"net/sched: cls_api: fix teardown of an adopted proto on insert-r","CVE":"CVE-2026-90248","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"90248","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: fix teardown of an adopted proto on insert-race loss\n\nIn tc_new_tfilter() the create branch sets tp_created = 1 before calling\ntcf_chain_tp_insert_unique(). When the caller loses the race (another\nrequest inserted a proto at the same chain/prio first), insert_unique()\ndestroys the caller's own tp_new and returns the winner's proto with an\nextra reference. tp_created was never cleared, so the loser's errout\npath treated the winner's live proto as its own and called\ntcf_chain_tp_delete_empty() on it, silently unlinking an active\nclassifier that the winning request already advertised via\nRTM_NEWTFILTER.\n\nTrack the outcome of the insert step in a single tri-state variable so\neach errout path reacts correctly:\n\n- TP_NOT_CREATED: no proto created; pursue the old path.\n- TP_CREATED: proto inserted successfully; same code path as before.\n- TP_NOT_OWNED: New - lost the insert race; tp is another request's proto\n  (chain ref already released by tp_new's destroy)\n\nBoth errout reactions are single expressions derived from the state.\n\nThis fix is motivated by the Sashiko's automated review of Patch\n(net/sched: cls_api: Always acquire rtnl_lock when destroying locked\nclassifiers) [1][2]. The review identified the silent-unlink behaviour of\nan adopted proto's teardown when a request loses the\ntcf_chain_tp_insert_unique() race.\n\n[1] https://sashiko.dev/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com\n[2] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260801125632.360365-1-jhs%40mojatatu.com","Type":"Description","Title":"net/sched: cls_api: fix teardown of an adopted proto on insert-r"}]}}}