{"api_version":"1","generated_at":"2026-05-12T18:10:47+00:00","cve":"CVE-2026-43323","urls":{"html":"https://cve.report/CVE-2026-43323","api":"https://cve.report/api/cve/CVE-2026-43323.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43323","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43323"},"summary":{"title":"sched/fair: Fix zero_vruntime tracking fix","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix zero_vruntime tracking fix\n\nJohn reported that stress-ng-yield could make his machine unhappy and\nmanaged to bisect it to commit b3d99f43c72b (\"sched/fair: Fix\nzero_vruntime tracking\").\n\nThe combination of yield and that commit was specific enough to\nhypothesize the following scenario:\n\nSuppose we have 2 runnable tasks, both doing yield. Then one will be\neligible and one will not be, because the average position must be in\nbetween these two entities.\n\nTherefore, the runnable task will be eligible, and be promoted a full\nslice (all the tasks do is yield after all). This causes it to jump over\nthe other task and now the other task is eligible and current is no\nlonger. So we schedule.\n\nSince we are runnable, there is no {de,en}queue. All we have is the\n__{en,de}queue_entity() from {put_prev,set_next}_task(). But per the\nfingered commit, those two no longer move zero_vruntime.\n\nAll that moves zero_vruntime are tick and full {de,en}queue.\n\nThis means, that if the two tasks playing leapfrog can reach the\ncritical speed to reach the overflow point inside one tick's worth of\ntime, we're up a creek.\n\nAdditionally, when multiple cgroups are involved, there is no guarantee\nthe tick will in fact hit every cgroup in a timely manner. Statistically\nspeaking it will, but that same statistics does not rule out the\npossibility of one cgroup not getting a tick for a significant amount of\ntime -- however unlikely.\n\nTherefore, just like with the yield() case, force an update at the end\nof every slice. This ensures the update is never more than a single\nslice behind and the whole thing is within 2 lag bounds as per the\ncomment on entity_key().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-08 14:16:40","updated_at":"2026-05-12 14:10:27"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/c089147074ed96ff4330739a0559394c19a3dfc8","name":"https://git.kernel.org/stable/c/c089147074ed96ff4330739a0559394c19a3dfc8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1319ea57529e131822bab56bf417c8edc2db9ae8","name":"https://git.kernel.org/stable/c/1319ea57529e131822bab56bf417c8edc2db9ae8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fb61ffb3fb30a161eb5404c27fc7635e275beafd","name":"https://git.kernel.org/stable/c/fb61ffb3fb30a161eb5404c27fc7635e275beafd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/87573883c30f1a8555ff720836bb6ea231058539","name":"https://git.kernel.org/stable/c/87573883c30f1a8555ff720836bb6ea231058539","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43323","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43323","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d2fc2dcfce47a56ffd414783003cc966c742c8a9 c089147074ed96ff4330739a0559394c19a3dfc8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 99673934a89febe664e704550216638dcb2336a8 87573883c30f1a8555ff720836bb6ea231058539 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 978d4fe59665c13db692ba96839f9c52d69f13f3 fb61ffb3fb30a161eb5404c27fc7635e275beafd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3d99f43c72b56cf7a104a364e7fb34b0702828b 1319ea57529e131822bab56bf417c8edc2db9ae8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.78 6.12.81 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.17 6.18.22 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.19.7 6.19.12 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"43323","cve":"CVE-2026-43323","epss":"0.000180000","percentile":"0.047280000","score_date":"2026-05-11","updated_at":"2026-05-12 00:01:18"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/sched/fair.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"c089147074ed96ff4330739a0559394c19a3dfc8","status":"affected","version":"d2fc2dcfce47a56ffd414783003cc966c742c8a9","versionType":"git"},{"lessThan":"87573883c30f1a8555ff720836bb6ea231058539","status":"affected","version":"99673934a89febe664e704550216638dcb2336a8","versionType":"git"},{"lessThan":"fb61ffb3fb30a161eb5404c27fc7635e275beafd","status":"affected","version":"978d4fe59665c13db692ba96839f9c52d69f13f3","versionType":"git"},{"lessThan":"1319ea57529e131822bab56bf417c8edc2db9ae8","status":"affected","version":"b3d99f43c72b56cf7a104a364e7fb34b0702828b","versionType":"git"}]},{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/sched/fair.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"6.12.81","status":"affected","version":"6.12.78","versionType":"semver"},{"lessThan":"6.18.22","status":"affected","version":"6.18.17","versionType":"semver"},{"lessThan":"6.19.12","status":"affected","version":"6.19.7","versionType":"semver"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.81","versionStartIncluding":"6.12.78","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.22","versionStartIncluding":"6.18.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.12","versionStartIncluding":"6.19.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix zero_vruntime tracking fix\n\nJohn reported that stress-ng-yield could make his machine unhappy and\nmanaged to bisect it to commit b3d99f43c72b (\"sched/fair: Fix\nzero_vruntime tracking\").\n\nThe combination of yield and that commit was specific enough to\nhypothesize the following scenario:\n\nSuppose we have 2 runnable tasks, both doing yield. Then one will be\neligible and one will not be, because the average position must be in\nbetween these two entities.\n\nTherefore, the runnable task will be eligible, and be promoted a full\nslice (all the tasks do is yield after all). This causes it to jump over\nthe other task and now the other task is eligible and current is no\nlonger. So we schedule.\n\nSince we are runnable, there is no {de,en}queue. All we have is the\n__{en,de}queue_entity() from {put_prev,set_next}_task(). But per the\nfingered commit, those two no longer move zero_vruntime.\n\nAll that moves zero_vruntime are tick and full {de,en}queue.\n\nThis means, that if the two tasks playing leapfrog can reach the\ncritical speed to reach the overflow point inside one tick's worth of\ntime, we're up a creek.\n\nAdditionally, when multiple cgroups are involved, there is no guarantee\nthe tick will in fact hit every cgroup in a timely manner. Statistically\nspeaking it will, but that same statistics does not rule out the\npossibility of one cgroup not getting a tick for a significant amount of\ntime -- however unlikely.\n\nTherefore, just like with the yield() case, force an update at the end\nof every slice. This ensures the update is never more than a single\nslice behind and the whole thing is within 2 lag bounds as per the\ncomment on entity_key()."}],"providerMetadata":{"dateUpdated":"2026-05-11T22:22:20.507Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/c089147074ed96ff4330739a0559394c19a3dfc8"},{"url":"https://git.kernel.org/stable/c/87573883c30f1a8555ff720836bb6ea231058539"},{"url":"https://git.kernel.org/stable/c/fb61ffb3fb30a161eb5404c27fc7635e275beafd"},{"url":"https://git.kernel.org/stable/c/1319ea57529e131822bab56bf417c8edc2db9ae8"}],"title":"sched/fair: Fix zero_vruntime tracking fix","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43323","datePublished":"2026-05-08T13:31:08.188Z","dateReserved":"2026-05-01T14:12:56.001Z","dateUpdated":"2026-05-11T22:22:20.507Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-08 14:16:40","lastModifiedDate":"2026-05-12 14:10:27","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43323","Ordinal":"1","Title":"sched/fair: Fix zero_vruntime tracking fix","CVE":"CVE-2026-43323","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43323","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix zero_vruntime tracking fix\n\nJohn reported that stress-ng-yield could make his machine unhappy and\nmanaged to bisect it to commit b3d99f43c72b (\"sched/fair: Fix\nzero_vruntime tracking\").\n\nThe combination of yield and that commit was specific enough to\nhypothesize the following scenario:\n\nSuppose we have 2 runnable tasks, both doing yield. Then one will be\neligible and one will not be, because the average position must be in\nbetween these two entities.\n\nTherefore, the runnable task will be eligible, and be promoted a full\nslice (all the tasks do is yield after all). This causes it to jump over\nthe other task and now the other task is eligible and current is no\nlonger. So we schedule.\n\nSince we are runnable, there is no {de,en}queue. All we have is the\n__{en,de}queue_entity() from {put_prev,set_next}_task(). But per the\nfingered commit, those two no longer move zero_vruntime.\n\nAll that moves zero_vruntime are tick and full {de,en}queue.\n\nThis means, that if the two tasks playing leapfrog can reach the\ncritical speed to reach the overflow point inside one tick's worth of\ntime, we're up a creek.\n\nAdditionally, when multiple cgroups are involved, there is no guarantee\nthe tick will in fact hit every cgroup in a timely manner. Statistically\nspeaking it will, but that same statistics does not rule out the\npossibility of one cgroup not getting a tick for a significant amount of\ntime -- however unlikely.\n\nTherefore, just like with the yield() case, force an update at the end\nof every slice. This ensures the update is never more than a single\nslice behind and the whole thing is within 2 lag bounds as per the\ncomment on entity_key().","Type":"Description","Title":"sched/fair: Fix zero_vruntime tracking fix"}]}}}