{"api_version":"1","generated_at":"2026-05-12T22:08:38+00:00","cve":"CVE-2026-43265","urls":{"html":"https://cve.report/CVE-2026-43265","api":"https://cve.report/api/cve/CVE-2026-43265.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43265","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43265"},"summary":{"title":"KVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()\n\nIgnore -EBUSY when checking nested events after exiting a blocking state\nwhile L2 is active, as exiting to userspace will generate a spurious\nuserspace exit, usually with KVM_EXIT_UNKNOWN, and likely lead to the VM's\ndemise.  Continuing with the wakeup isn't perfect either, as *something*\nhas gone sideways if a vCPU is awakened in L2 with an injected event (or\nworse, a nested run pending), but continuing on gives the VM a decent\nchance of surviving without any major side effects.\n\nAs explained in the Fixes commits, it _should_ be impossible for a vCPU to\nbe put into a blocking state with an already-injected event (exception,\nIRQ, or NMI).  Unfortunately, userspace can stuff MP_STATE and/or injected\nevents, and thus put the vCPU into what should be an impossible state.\n\nDon't bother trying to preserve the WARN, e.g. with an anti-syzkaller\nKconfig, as WARNs can (hopefully) be added in paths where _KVM_ would be\nviolating x86 architecture, e.g. by WARNing if KVM attempts to inject an\nexception or interrupt while the vCPU isn't running.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-06 12:16:47","updated_at":"2026-05-08 20:33:43"},"problem_types":["NVD-CWE-noinfo"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/ec3be7dc9391085a2d96700e159d66d1328b7ff6","name":"https://git.kernel.org/stable/c/ec3be7dc9391085a2d96700e159d66d1328b7ff6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2657439265d34a911886b916ba8be97ecc117d51","name":"https://git.kernel.org/stable/c/2657439265d34a911886b916ba8be97ecc117d51","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/78265cd066d73a5cb41c088fcae4a2515e480d97","name":"https://git.kernel.org/stable/c/78265cd066d73a5cb41c088fcae4a2515e480d97","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1c957773063ed3264953597e32990a748381caf6","name":"https://git.kernel.org/stable/c/1c957773063ed3264953597e32990a748381caf6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1e88b5f854bdb469424132e0bb44793ad7a7c20a","name":"https://git.kernel.org/stable/c/1e88b5f854bdb469424132e0bb44793ad7a7c20a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ead63640d4e72e6f6d464f4e31f7fecb79af8869","name":"https://git.kernel.org/stable/c/ead63640d4e72e6f6d464f4e31f7fecb79af8869","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43265","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43265","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 26844fee6adee9b1557d2279b0506285de9ee82b 78265cd066d73a5cb41c088fcae4a2515e480d97 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 26844fee6adee9b1557d2279b0506285de9ee82b ec3be7dc9391085a2d96700e159d66d1328b7ff6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 26844fee6adee9b1557d2279b0506285de9ee82b 2657439265d34a911886b916ba8be97ecc117d51 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 26844fee6adee9b1557d2279b0506285de9ee82b 1e88b5f854bdb469424132e0bb44793ad7a7c20a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * 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the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()\n\nIgnore -EBUSY when checking nested events after exiting a blocking state\nwhile L2 is active, as exiting to userspace will generate a spurious\nuserspace exit, usually with KVM_EXIT_UNKNOWN, and likely lead to the VM's\ndemise.  Continuing with the wakeup isn't perfect either, as *something*\nhas gone sideways if a vCPU is awakened in L2 with an injected event (or\nworse, a nested run pending), but continuing on gives the VM a decent\nchance of surviving without any major side effects.\n\nAs explained in the Fixes commits, it _should_ be impossible for a vCPU to\nbe put into a blocking state with an already-injected event (exception,\nIRQ, or NMI).  Unfortunately, userspace can stuff MP_STATE and/or injected\nevents, and thus put the vCPU into what should be an impossible state.\n\nDon't bother trying to preserve the WARN, e.g. with an anti-syzkaller\nKconfig, as WARNs can (hopefully) be added in paths where _KVM_ would be\nviolating x86 architecture, e.g. by WARNing if KVM attempts to inject an\nexception or interrupt while the vCPU isn't running."}],"providerMetadata":{"dateUpdated":"2026-05-06T11:28:51.552Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/78265cd066d73a5cb41c088fcae4a2515e480d97"},{"url":"https://git.kernel.org/stable/c/ec3be7dc9391085a2d96700e159d66d1328b7ff6"},{"url":"https://git.kernel.org/stable/c/2657439265d34a911886b916ba8be97ecc117d51"},{"url":"https://git.kernel.org/stable/c/1e88b5f854bdb469424132e0bb44793ad7a7c20a"},{"url":"https://git.kernel.org/stable/c/1c957773063ed3264953597e32990a748381caf6"},{"url":"https://git.kernel.org/stable/c/ead63640d4e72e6f6d464f4e31f7fecb79af8869"}],"title":"KVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43265","datePublished":"2026-05-06T11:28:51.552Z","dateReserved":"2026-05-01T14:12:55.997Z","dateUpdated":"2026-05-06T11:28:51.552Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-06 12:16:47","lastModifiedDate":"2026-05-08 20:33:43","problem_types":["NVD-CWE-noinfo"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.1.167","matchCriteriaId":"C54AECAF-D924-45D0-89E2-77D4D1CC2E8E"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.130","matchCriteriaId":"C57BB918-DF28-46B3-94F7-144176841267"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.77","matchCriteriaId":"B3D12E00-E42D-4056-B354-BAD4903C03A5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.17","matchCriteriaId":"A5E006E4-59C7-43C1-9231-62A72219F2BA"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"6.19.6","matchCriteriaId":"373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43265","Ordinal":"1","Title":"KVM: x86: Ignore -EBUSY when checking nested events from vcpu_bl","CVE":"CVE-2026-43265","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43265","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()\n\nIgnore -EBUSY when checking nested events after exiting a blocking state\nwhile L2 is active, as exiting to userspace will generate a spurious\nuserspace exit, usually with KVM_EXIT_UNKNOWN, and likely lead to the VM's\ndemise.  Continuing with the wakeup isn't perfect either, as *something*\nhas gone sideways if a vCPU is awakened in L2 with an injected event (or\nworse, a nested run pending), but continuing on gives the VM a decent\nchance of surviving without any major side effects.\n\nAs explained in the Fixes commits, it _should_ be impossible for a vCPU to\nbe put into a blocking state with an already-injected event (exception,\nIRQ, or NMI).  Unfortunately, userspace can stuff MP_STATE and/or injected\nevents, and thus put the vCPU into what should be an impossible state.\n\nDon't bother trying to preserve the WARN, e.g. with an anti-syzkaller\nKconfig, as WARNs can (hopefully) be added in paths where _KVM_ would be\nviolating x86 architecture, e.g. by WARNing if KVM attempts to inject an\nexception or interrupt while the vCPU isn't running.","Type":"Description","Title":"KVM: x86: Ignore -EBUSY when checking nested events from vcpu_bl"}]}}}