FKIE_CVE-2026-74580

Vulnerability from fkie_nvd - Published: 2026-08-21 17:16 - Updated: 2026-08-25 06:18
Severity
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: vhost: reset the vring metadata cache on vring reconfiguration vq->meta_iotlb[] caches the vhost_iotlb_map that backs each vring metadata region, and iotlb_access_ok() returns early on a cache hit, taking the hit as proof that the region has already been validated: if (vhost_vq_meta_fetch(vq, addr, len, type)) return true; The cache is reset on VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE, on device IOTLB (re)initialisation and on vq reset, but not when VHOST_SET_VRING_ADDR replaces vq->desc, vq->avail and vq->used, nor when VHOST_SET_VRING_NUM changes the region sizes. With a device IOTLB attached both ioctls are accepted while the vq is live, and neither validates the addresses at ioctl time: vq_access_ok() and vq_log_used_access_ok() return true early because the addresses are GIOVAs, deferring validation to prefetch time. Once the cache has been populated that deferred validation no longer runs -- vq_meta_prefetch() hits the stale entry and returns true -- and vhost_vq_meta_fetch() keeps translating through the old mapping as map->addr + addr - map->start for an address the mapping no longer covers. vhost_copy_to_user() and vhost_copy_from_user() consume the result with __copy_to_user() and __copy_from_user(), which do not check it either, so a subsequent used ring update or descriptor fetch accesses memory outside the region the IOTLB actually maps. Reset the metadata cache whenever the vring is reconfigured, so the new addresses are pushed back through iotlb_access_ok()'s slow path.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/13fa6f32a56a386a82bd7451644c494beed034af
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5224bd37e37d36076a550d99b2aebba33939fd95
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/54617e9119be2eb728ecdd8d977b99c99d4c498a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6fa3e9b1fe856259555a7e22f3f3082e7827fd9b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b70ebe0bba254e093dd5fd4c0c170941ce83eb85
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/de845981da67a6b049080c87e605130b0c30adc5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/vhost/vhost.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5224bd37e37d36076a550d99b2aebba33939fd95",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            },
            {
              "lessThan": "54617e9119be2eb728ecdd8d977b99c99d4c498a",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            },
            {
              "lessThan": "13fa6f32a56a386a82bd7451644c494beed034af",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            },
            {
              "lessThan": "cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            },
            {
              "lessThan": "6fa3e9b1fe856259555a7e22f3f3082e7827fd9b",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            },
            {
              "lessThan": "f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            },
            {
              "lessThan": "b70ebe0bba254e093dd5fd4c0c170941ce83eb85",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            },
            {
              "lessThan": "de845981da67a6b049080c87e605130b0c30adc5",
              "status": "affected",
              "version": "f889491380582b4ba2981cf0b0d7d6a40fb30ab7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/vhost/vhost.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.11"
            },
            {
              "lessThan": "4.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost: reset the vring metadata cache on vring reconfiguration\n\nvq-\u003emeta_iotlb[] caches the vhost_iotlb_map that backs each vring\nmetadata region, and iotlb_access_ok() returns early on a cache hit,\ntaking the hit as proof that the region has already been validated:\n\n\tif (vhost_vq_meta_fetch(vq, addr, len, type))\n\t\treturn true;\n\nThe cache is reset on VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE, on\ndevice IOTLB (re)initialisation and on vq reset, but not when\nVHOST_SET_VRING_ADDR replaces vq-\u003edesc, vq-\u003eavail and vq-\u003eused, nor when\nVHOST_SET_VRING_NUM changes the region sizes.\n\nWith a device IOTLB attached both ioctls are accepted while the vq is\nlive, and neither validates the addresses at ioctl time: vq_access_ok()\nand vq_log_used_access_ok() return true early because the addresses are\nGIOVAs, deferring validation to prefetch time.  Once the cache has been\npopulated that deferred validation no longer runs -- vq_meta_prefetch()\nhits the stale entry and returns true -- and vhost_vq_meta_fetch() keeps\ntranslating through the old mapping as\n\n\tmap-\u003eaddr + addr - map-\u003estart\n\nfor an address the mapping no longer covers.  vhost_copy_to_user() and\nvhost_copy_from_user() consume the result with __copy_to_user() and\n__copy_from_user(), which do not check it either, so a subsequent used\nring update or descriptor fetch accesses memory outside the region the\nIOTLB actually maps.\n\nReset the metadata cache whenever the vring is reconfigured, so the new\naddresses are pushed back through iotlb_access_ok()\u0027s slow path."
    }
  ],
  "id": "CVE-2026-74580",
  "lastModified": "2026-08-25T06:18:30.997",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 6.0,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-21T17:16:44.210",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/13fa6f32a56a386a82bd7451644c494beed034af"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5224bd37e37d36076a550d99b2aebba33939fd95"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/54617e9119be2eb728ecdd8d977b99c99d4c498a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6fa3e9b1fe856259555a7e22f3f3082e7827fd9b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b70ebe0bba254e093dd5fd4c0c170941ce83eb85"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/de845981da67a6b049080c87e605130b0c30adc5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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