{"api_version":"1","generated_at":"2026-05-13T03:25:58+00:00","cve":"CVE-2026-43392","urls":{"html":"https://cve.report/CVE-2026-43392","api":"https://cve.report/api/cve/CVE-2026-43392.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43392","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43392"},"summary":{"title":"sched_ext: Fix starvation of scx_enable() under fair-class saturation","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix starvation of scx_enable() under fair-class saturation\n\nDuring scx_enable(), the READY -> ENABLED task switching loop changes the\ncalling thread's sched_class from fair to ext. Since fair has higher\npriority than ext, saturating fair-class workloads can indefinitely starve\nthe enable thread, hanging the system. This was introduced when the enable\npath switched from preempt_disable() to scx_bypass() which doesn't protect\nagainst fair-class starvation. Note that the original preempt_disable()\nprotection wasn't complete either - in partial switch modes, the calling\nthread could still be starved after preempt_enable() as it may have been\nswitched to ext class.\n\nFix it by offloading the enable body to a dedicated system-wide RT\n(SCHED_FIFO) kthread which cannot be starved by either fair or ext class\ntasks. scx_enable() lazily creates the kthread on first use and passes the\nops pointer through a struct scx_enable_cmd containing the kthread_work,\nthen synchronously waits for completion.\n\nThe workfn runs on a different kthread from sch->helper (which runs\ndisable_work), so it can safely flush disable_work on the error path\nwithout deadlock.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-08 15:16:50","updated_at":"2026-05-12 14:10:27"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/05ab9ec5dc24f234e0a2fecf3e6ff937c68f7d81","name":"https://git.kernel.org/stable/c/05ab9ec5dc24f234e0a2fecf3e6ff937c68f7d81","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c44198f25fdfecc0ec0fe366bf8a47fe17d8e229","name":"https://git.kernel.org/stable/c/c44198f25fdfecc0ec0fe366bf8a47fe17d8e229","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b06ccbabe2506fd70b9167a644978b049150224a","name":"https://git.kernel.org/stable/c/b06ccbabe2506fd70b9167a644978b049150224a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e0b14bf06393be137d3efb6a3b7cd5b4b9810a6b","name":"https://git.kernel.org/stable/c/e0b14bf06393be137d3efb6a3b7cd5b4b9810a6b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43392","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43392","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8c2090c504e998c8f34ec870bae71dafcc96a6e0 e0b14bf06393be137d3efb6a3b7cd5b4b9810a6b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8c2090c504e998c8f34ec870bae71dafcc96a6e0 c44198f25fdfecc0ec0fe366bf8a47fe17d8e229 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8c2090c504e998c8f34ec870bae71dafcc96a6e0 05ab9ec5dc24f234e0a2fecf3e6ff937c68f7d81 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8c2090c504e998c8f34ec870bae71dafcc96a6e0 b06ccbabe2506fd70b9167a644978b049150224a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.78 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.20 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.9 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"43392","cve":"CVE-2026-43392","epss":"0.000180000","percentile":"0.047270000","score_date":"2026-05-12","updated_at":"2026-05-13 00:11:53"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/sched/ext.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"e0b14bf06393be137d3efb6a3b7cd5b4b9810a6b","status":"affected","version":"8c2090c504e998c8f34ec870bae71dafcc96a6e0","versionType":"git"},{"lessThan":"c44198f25fdfecc0ec0fe366bf8a47fe17d8e229","status":"affected","version":"8c2090c504e998c8f34ec870bae71dafcc96a6e0","versionType":"git"},{"lessThan":"05ab9ec5dc24f234e0a2fecf3e6ff937c68f7d81","status":"affected","version":"8c2090c504e998c8f34ec870bae71dafcc96a6e0","versionType":"git"},{"lessThan":"b06ccbabe2506fd70b9167a644978b049150224a","status":"affected","version":"8c2090c504e998c8f34ec870bae71dafcc96a6e0","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/sched/ext.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.12"},{"lessThan":"6.12","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.78","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.20","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.78","versionStartIncluding":"6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.20","versionStartIncluding":"6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.9","versionStartIncluding":"6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"6.12","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix starvation of scx_enable() under fair-class saturation\n\nDuring scx_enable(), the READY -> ENABLED task switching loop changes the\ncalling thread's sched_class from fair to ext. Since fair has higher\npriority than ext, saturating fair-class workloads can indefinitely starve\nthe enable thread, hanging the system. This was introduced when the enable\npath switched from preempt_disable() to scx_bypass() which doesn't protect\nagainst fair-class starvation. Note that the original preempt_disable()\nprotection wasn't complete either - in partial switch modes, the calling\nthread could still be starved after preempt_enable() as it may have been\nswitched to ext class.\n\nFix it by offloading the enable body to a dedicated system-wide RT\n(SCHED_FIFO) kthread which cannot be starved by either fair or ext class\ntasks. scx_enable() lazily creates the kthread on first use and passes the\nops pointer through a struct scx_enable_cmd containing the kthread_work,\nthen synchronously waits for completion.\n\nThe workfn runs on a different kthread from sch->helper (which runs\ndisable_work), so it can safely flush disable_work on the error path\nwithout deadlock."}],"providerMetadata":{"dateUpdated":"2026-05-11T22:23:41.885Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e0b14bf06393be137d3efb6a3b7cd5b4b9810a6b"},{"url":"https://git.kernel.org/stable/c/c44198f25fdfecc0ec0fe366bf8a47fe17d8e229"},{"url":"https://git.kernel.org/stable/c/05ab9ec5dc24f234e0a2fecf3e6ff937c68f7d81"},{"url":"https://git.kernel.org/stable/c/b06ccbabe2506fd70b9167a644978b049150224a"}],"title":"sched_ext: Fix starvation of scx_enable() under fair-class saturation","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43392","datePublished":"2026-05-08T14:21:36.692Z","dateReserved":"2026-05-01T14:12:56.007Z","dateUpdated":"2026-05-11T22:23:41.885Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-08 15:16:50","lastModifiedDate":"2026-05-12 14:10:27","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43392","Ordinal":"1","Title":"sched_ext: Fix starvation of scx_enable() under fair-class satur","CVE":"CVE-2026-43392","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43392","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix starvation of scx_enable() under fair-class saturation\n\nDuring scx_enable(), the READY -> ENABLED task switching loop changes the\ncalling thread's sched_class from fair to ext. Since fair has higher\npriority than ext, saturating fair-class workloads can indefinitely starve\nthe enable thread, hanging the system. This was introduced when the enable\npath switched from preempt_disable() to scx_bypass() which doesn't protect\nagainst fair-class starvation. Note that the original preempt_disable()\nprotection wasn't complete either - in partial switch modes, the calling\nthread could still be starved after preempt_enable() as it may have been\nswitched to ext class.\n\nFix it by offloading the enable body to a dedicated system-wide RT\n(SCHED_FIFO) kthread which cannot be starved by either fair or ext class\ntasks. scx_enable() lazily creates the kthread on first use and passes the\nops pointer through a struct scx_enable_cmd containing the kthread_work,\nthen synchronously waits for completion.\n\nThe workfn runs on a different kthread from sch->helper (which runs\ndisable_work), so it can safely flush disable_work on the error path\nwithout deadlock.","Type":"Description","Title":"sched_ext: Fix starvation of scx_enable() under fair-class satur"}]}}}