{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "fb04a1eddb1a65b6588a021bdc132270d5ae48bb"
            },
            {
              "fixed": "74f1a22f7a80f03d28ad8551a2d25d563433addf"
            },
            {
              "fixed": "0eb281eb95b2d4eea4db1da5fe91023aecc97095"
            },
            {
              "fixed": "01b71b930f15728aa8599478a7ce90c19dcd9fc2"
            },
            {
              "fixed": "b315b033a877b1ee6d827810b5d7bb4392ffcf8d"
            },
            {
              "fixed": "0d419c23bb11b5c9664de777c47c1f04a235882d"
            },
            {
              "fixed": "ecf9b3ea7847fe14f34b8c41f00de1eb95c747da"
            },
            {
              "fixed": "577a8d3bae0531f0e5ccfac919cd8192f920a804"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.209"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.175"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.141"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.91"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.33"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52969.json"
  },
  "details": "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)) \u003e= memslot-\u003enpages)\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-\u003earch.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-\u003enpages is bounded well below U64_MAX, so once offset \u003c\nnpages holds, offset + __fls(mask) (with __fls(mask) \u003c BITS_PER_LONG)\nstays in range.",
  "id": "CVE-2026-52969",
  "modified": "2026-07-08T05:36:23.552055538Z",
  "published": "2026-06-24T16:28:48.085Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/01b71b930f15728aa8599478a7ce90c19dcd9fc2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0d419c23bb11b5c9664de777c47c1f04a235882d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0eb281eb95b2d4eea4db1da5fe91023aecc97095"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/577a8d3bae0531f0e5ccfac919cd8192f920a804"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/74f1a22f7a80f03d28ad8551a2d25d563433addf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b315b033a877b1ee6d827810b5d7bb4392ffcf8d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ecf9b3ea7847fe14f34b8c41f00de1eb95c747da"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52969.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-52969"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52969.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52969"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492434"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "KVM: Reject wrapped offset in kvm_reset_dirty_gfn()"
}