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CVE-2022-33745

Status: ModifiedHigh (8.8)—

insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. To address XSA-401, code was moved inside a function in Xen. This code movement missed a variable changing meaning / value between old and new code positions. The now wrong use of the variable did lead to a wrong TLB flush condition, omitting flushes where such are necessary.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (3)

Debian — Debian LinuxFedoraproject — FedoraXEN — XEN

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2022-33745",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 2
      }
    ]
  },
  "affected": [
    {
      "source": "security@xen.org",
      "affectedData": [
        {
          "vendor": "Xen",
          "product": "xen",
          "versions": [
            {
              "status": "unknown",
              "version": "consult Xen advisory XSA-408"
            }
          ]
        }
      ]
    }
  ],
  "published": "2022-07-26T13:15:10.003",
  "references": [
    {
      "url": "http://www.openwall.com/lists/oss-security/2022/07/26/2",
      "tags": [
        "Mailing List",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "security@xen.org"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2022/07/26/3",
      "tags": [
        "Mailing List",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "security@xen.org"
    },
    {
      "url": "http://xenbits.xen.org/xsa/advisory-408.html",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "security@xen.org"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HUFIMNGYP5VQAA6KE3T2I5GW6UP6F7BS/",
      "source": "security@xen.org"
    },
    {
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      "source": "security@xen.org"
    },
    {
      "url": "https://www.debian.org/security/2022/dsa-5272",
      "tags": [
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      ],
      "source": "security@xen.org"
    },
    {
      "url": "https://xenbits.xenproject.org/xsa/advisory-408.txt",
      "tags": [
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      ],
      "source": "security@xen.org"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2022/07/26/2",
      "tags": [
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        "Patch",
        "Third Party Advisory"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
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      "tags": [
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        "Patch",
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
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      "tags": [
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HUFIMNGYP5VQAA6KE3T2I5GW6UP6F7BS/",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MYI3OMJ7RIZNL3C6GUWNANNPEUUID6FM/",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.debian.org/security/2022/dsa-5272",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://xenbits.xenproject.org/xsa/advisory-408.txt",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. To address XSA-401, code was moved inside a function in Xen. This code movement missed a variable changing meaning / value between old and new code positions. The now wrong use of the variable did lead to a wrong TLB flush condition, omitting flushes where such are necessary."
    },
    {
      "lang": "es",
      "value": "Un vaciado insuficiente del TLB para huéspedes x86 PV en modo de sombra Para la migración, así como para trabajar en torno a los kernels que no son conscientes de L1TF (véase XSA-273), los huéspedes PV pueden ejecutarse en modo de paginación de sombra. Para abordar XSA-401, el código fue movido dentro de una función en Xen. Este movimiento de código pasó por alto una variable que cambiaba de significado/valor entre las posiciones de código antiguas y nuevas. El uso ahora erróneo de la variable conllevaba a una condición errónea de vaciado de la TLB, omitiendo el vaciado cuando era necesario."
    }
  ],
  "lastModified": "2026-06-17T04:49:21.813",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:*",
              "vulnerable": true,
              "matchCriteriaId": "EF4E17C2-244F-4E5A-A5F8-4626CD1AC11A"
            }
          ],
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FA6FEEC2-9F11-4643-8827-749718254FED"
            },
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "80E516C0-98A4-4ADE-B69F-66A772E2BAAA"
            },
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "5C675112-476C-4D7C-BCB9-A2FB2D0BC9FD"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@xen.org"
}