{"api_version":"1","generated_at":"2026-06-26T08:34:05+00:00","cve":"CVE-2026-52969","urls":{"html":"https://cve.report/CVE-2026-52969","api":"https://cve.report/api/cve/CVE-2026-52969.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-52969","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-52969"},"summary":{"title":"KVM: Reject wrapped offset in kvm_reset_dirty_gfn()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Reject wrapped offset in kvm_reset_dirty_gfn()\n\nkvm_reset_dirty_gfn() guards the gfn range with\n\n\tif (!memslot || (offset + __fls(mask)) >= memslot->npages)\n\t\treturn;\n\nbut offset is u64 and the addition is unchecked.  The check can be\nsilently bypassed by a u64 wrap.\n\nThe dirty ring backing those entries is MAP_SHARED at\nKVM_DIRTY_LOG_PAGE_OFFSET of the vcpu fd, so the VMM can rewrite the\nslot and offset fields of any entry between when the kernel pushes\nthem and when KVM_RESET_DIRTY_RINGS consumes them.  On reset,\nkvm_dirty_ring_reset() re-reads the values via READ_ONCE() and feeds\nthem straight back into this check; only the flags handshake is\ntreated as the handover, the slot/offset payload is taken on trust.\n\nCrafting two entries\n\n\tentry[i].offset   = 0xffffffffffffffc1\n\tentry[i+1].offset = 0\n\nmakes the coalescing loop in kvm_dirty_ring_reset() compute\n\n\tdelta = (s64)(0 - 0xffffffffffffffc1) = 63\n\nwhich falls in [0, BITS_PER_LONG), so it folds entry[i+1] into the\nexisting mask by setting bit 63.  The trailing kvm_reset_dirty_gfn()\ncall then sees offset = 0xffffffffffffffc1 and __fls(mask) = 63;\nthe sum is 0 in u64 and the bounds check passes.\n\nThat offset propagates into kvm_arch_mmu_enable_log_dirty_pt_masked()\nunchanged.  On the legacy MMU path -- kvm_memslots_have_rmaps() ==\ntrue, i.e. shadow paging, any VM that has allocated shadow roots, or\na write-tracked slot -- it reaches gfn_to_rmap(), which indexes\nslot->arch.rmap[0][] with a near-U64_MAX gfn.  That is an\nout-of-bounds load of a kvm_rmap_head, followed by a conditional\nclear of PT_WRITABLE_MASK in whatever the loaded pointer points at.\nThe path is reachable from any process holding /dev/kvm.\n\nRange-check offset on its own first, so the addition cannot wrap.\nmemslot->npages is bounded well below U64_MAX, so once offset <\nnpages holds, offset + __fls(mask) (with __fls(mask) < BITS_PER_LONG)\nstays in range.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-06-24 17:17:07","updated_at":"2026-06-24 17:17:07"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/ecf9b3ea7847fe14f34b8c41f00de1eb95c747da","name":"https://git.kernel.org/stable/c/ecf9b3ea7847fe14f34b8c41f00de1eb95c747da","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/01b71b930f15728aa8599478a7ce90c19dcd9fc2","name":"https://git.kernel.org/stable/c/01b71b930f15728aa8599478a7ce90c19dcd9fc2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0eb281eb95b2d4eea4db1da5fe91023aecc97095","name":"https://git.kernel.org/stable/c/0eb281eb95b2d4eea4db1da5fe91023aecc97095","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/577a8d3bae0531f0e5ccfac919cd8192f920a804","name":"https://git.kernel.org/stable/c/577a8d3bae0531f0e5ccfac919cd8192f920a804","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b315b033a877b1ee6d827810b5d7bb4392ffcf8d","name":"https://git.kernel.org/stable/c/b315b033a877b1ee6d827810b5d7bb4392ffcf8d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0d419c23bb11b5c9664de777c47c1f04a235882d","name":"https://git.kernel.org/stable/c/0d419c23bb11b5c9664de777c47c1f04a235882d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/74f1a22f7a80f03d28ad8551a2d25d563433addf","name":"https://git.kernel.org/stable/c/74f1a22f7a80f03d28ad8551a2d25d563433addf","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-52969","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52969","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fb04a1eddb1a65b6588a021bdc132270d5ae48bb 74f1a22f7a80f03d28ad8551a2d25d563433addf git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fb04a1eddb1a65b6588a021bdc132270d5ae48bb 0eb281eb95b2d4eea4db1da5fe91023aecc97095 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fb04a1eddb1a65b6588a021bdc132270d5ae48bb 01b71b930f15728aa8599478a7ce90c19dcd9fc2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fb04a1eddb1a65b6588a021bdc132270d5ae48bb b315b033a877b1ee6d827810b5d7bb4392ffcf8d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fb04a1eddb1a65b6588a021bdc132270d5ae48bb 0d419c23bb11b5c9664de777c47c1f04a235882d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fb04a1eddb1a65b6588a021bdc132270d5ae48bb ecf9b3ea7847fe14f34b8c41f00de1eb95c747da git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fb04a1eddb1a65b6588a021bdc132270d5ae48bb 577a8d3bae0531f0e5ccfac919cd8192f920a804 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.11","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.209 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.175 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.141 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.91 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.33 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.10 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"52969","cve":"CVE-2026-52969","epss":"0.001890000","percentile":"0.086920000","score_date":"2026-06-25","updated_at":"2026-06-26 00:06:15"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["virt/kvm/dirty_ring.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"74f1a22f7a80f03d28ad8551a2d25d563433addf","status":"affected","version":"fb04a1eddb1a65b6588a021bdc132270d5ae48bb","versionType":"git"},{"lessThan":"0eb281eb95b2d4eea4db1da5fe91023aecc97095","status":"affected","version":"fb04a1eddb1a65b6588a021bdc132270d5ae48bb","versionType":"git"},{"lessThan":"01b71b930f15728aa8599478a7ce90c19dcd9fc2","status":"affected","version":"fb04a1eddb1a65b6588a021bdc132270d5ae48bb","versionType":"git"},{"lessThan":"b315b033a877b1ee6d827810b5d7bb4392ffcf8d","status":"affected","version":"fb04a1eddb1a65b6588a021bdc132270d5ae48bb","versionType":"git"},{"lessThan":"0d419c23bb11b5c9664de777c47c1f04a235882d","status":"affected","version":"fb04a1eddb1a65b6588a021bdc132270d5ae48bb","versionType":"git"},{"lessThan":"ecf9b3ea7847fe14f34b8c41f00de1eb95c747da","status":"affected","version":"fb04a1eddb1a65b6588a021bdc132270d5ae48bb","versionType":"git"},{"lessThan":"577a8d3bae0531f0e5ccfac919cd8192f920a804","status":"affected","version":"fb04a1eddb1a65b6588a021bdc132270d5ae48bb","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["virt/kvm/dirty_ring.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.11"},{"lessThan":"5.11","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.209","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.175","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.141","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.91","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.33","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.209","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.175","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.141","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.91","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.33","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.10","versionStartIncluding":"5.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"5.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Reject wrapped offset in kvm_reset_dirty_gfn()\n\nkvm_reset_dirty_gfn() guards the gfn range with\n\n\tif (!memslot || (offset + __fls(mask)) >= memslot->npages)\n\t\treturn;\n\nbut offset is u64 and the addition is unchecked.  The check can be\nsilently bypassed by a u64 wrap.\n\nThe dirty ring backing those entries is MAP_SHARED at\nKVM_DIRTY_LOG_PAGE_OFFSET of the vcpu fd, so the VMM can rewrite the\nslot and offset fields of any entry between when the kernel pushes\nthem and when KVM_RESET_DIRTY_RINGS consumes them.  On reset,\nkvm_dirty_ring_reset() re-reads the values via READ_ONCE() and feeds\nthem straight back into this check; only the flags handshake is\ntreated as the handover, the slot/offset payload is taken on trust.\n\nCrafting two entries\n\n\tentry[i].offset   = 0xffffffffffffffc1\n\tentry[i+1].offset = 0\n\nmakes the coalescing loop in kvm_dirty_ring_reset() compute\n\n\tdelta = (s64)(0 - 0xffffffffffffffc1) = 63\n\nwhich falls in [0, BITS_PER_LONG), so it folds entry[i+1] into the\nexisting mask by setting bit 63.  The trailing kvm_reset_dirty_gfn()\ncall then sees offset = 0xffffffffffffffc1 and __fls(mask) = 63;\nthe sum is 0 in u64 and the bounds check passes.\n\nThat offset propagates into kvm_arch_mmu_enable_log_dirty_pt_masked()\nunchanged.  On the legacy MMU path -- kvm_memslots_have_rmaps() ==\ntrue, i.e. shadow paging, any VM that has allocated shadow roots, or\na write-tracked slot -- it reaches gfn_to_rmap(), which indexes\nslot->arch.rmap[0][] with a near-U64_MAX gfn.  That is an\nout-of-bounds load of a kvm_rmap_head, followed by a conditional\nclear of PT_WRITABLE_MASK in whatever the loaded pointer points at.\nThe path is reachable from any process holding /dev/kvm.\n\nRange-check offset on its own first, so the addition cannot wrap.\nmemslot->npages is bounded well below U64_MAX, so once offset <\nnpages holds, offset + __fls(mask) (with __fls(mask) < BITS_PER_LONG)\nstays in range."}],"providerMetadata":{"dateUpdated":"2026-06-24T16:28:48.085Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/74f1a22f7a80f03d28ad8551a2d25d563433addf"},{"url":"https://git.kernel.org/stable/c/0eb281eb95b2d4eea4db1da5fe91023aecc97095"},{"url":"https://git.kernel.org/stable/c/01b71b930f15728aa8599478a7ce90c19dcd9fc2"},{"url":"https://git.kernel.org/stable/c/b315b033a877b1ee6d827810b5d7bb4392ffcf8d"},{"url":"https://git.kernel.org/stable/c/0d419c23bb11b5c9664de777c47c1f04a235882d"},{"url":"https://git.kernel.org/stable/c/ecf9b3ea7847fe14f34b8c41f00de1eb95c747da"},{"url":"https://git.kernel.org/stable/c/577a8d3bae0531f0e5ccfac919cd8192f920a804"}],"title":"KVM: Reject wrapped offset in kvm_reset_dirty_gfn()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-52969","datePublished":"2026-06-24T16:28:48.085Z","dateReserved":"2026-06-09T07:44:35.375Z","dateUpdated":"2026-06-24T16:28:48.085Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-24 17:17:07","lastModifiedDate":"2026-06-24 17:17:07","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"52969","Ordinal":"1","Title":"KVM: Reject wrapped offset in kvm_reset_dirty_gfn()","CVE":"CVE-2026-52969","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"52969","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Reject wrapped offset in kvm_reset_dirty_gfn()\n\nkvm_reset_dirty_gfn() guards the gfn range with\n\n\tif (!memslot || (offset + __fls(mask)) >= memslot->npages)\n\t\treturn;\n\nbut offset is u64 and the addition is unchecked.  The check can be\nsilently bypassed by a u64 wrap.\n\nThe dirty ring backing those entries is MAP_SHARED at\nKVM_DIRTY_LOG_PAGE_OFFSET of the vcpu fd, so the VMM can rewrite the\nslot and offset fields of any entry between when the kernel pushes\nthem and when KVM_RESET_DIRTY_RINGS consumes them.  On reset,\nkvm_dirty_ring_reset() re-reads the values via READ_ONCE() and feeds\nthem straight back into this check; only the flags handshake is\ntreated as the handover, the slot/offset payload is taken on trust.\n\nCrafting two entries\n\n\tentry[i].offset   = 0xffffffffffffffc1\n\tentry[i+1].offset = 0\n\nmakes the coalescing loop in kvm_dirty_ring_reset() compute\n\n\tdelta = (s64)(0 - 0xffffffffffffffc1) = 63\n\nwhich falls in [0, BITS_PER_LONG), so it folds entry[i+1] into the\nexisting mask by setting bit 63.  The trailing kvm_reset_dirty_gfn()\ncall then sees offset = 0xffffffffffffffc1 and __fls(mask) = 63;\nthe sum is 0 in u64 and the bounds check passes.\n\nThat offset propagates into kvm_arch_mmu_enable_log_dirty_pt_masked()\nunchanged.  On the legacy MMU path -- kvm_memslots_have_rmaps() ==\ntrue, i.e. shadow paging, any VM that has allocated shadow roots, or\na write-tracked slot -- it reaches gfn_to_rmap(), which indexes\nslot->arch.rmap[0][] with a near-U64_MAX gfn.  That is an\nout-of-bounds load of a kvm_rmap_head, followed by a conditional\nclear of PT_WRITABLE_MASK in whatever the loaded pointer points at.\nThe path is reachable from any process holding /dev/kvm.\n\nRange-check offset on its own first, so the addition cannot wrap.\nmemslot->npages is bounded well below U64_MAX, so once offset <\nnpages holds, offset + __fls(mask) (with __fls(mask) < BITS_PER_LONG)\nstays in range.","Type":"Description","Title":"KVM: Reject wrapped offset in kvm_reset_dirty_gfn()"}]}}}