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[email protected]CVE-2021-28697

HistoryAug 27, 2021 - 7:15 p.m.

CVE-2021-28697

2021-08-2719:15:07

CWE-362

[email protected]

web.nvd.nist.gov

119

cve-2021-28697

grant table

status pages

memory

xen

guest

hypervisor

security

4.6 Medium

CVSS2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:L/Au:N/C:P/I:P/A:P

7.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

7.5 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

14.3%

JSON

grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests from the guest to insert mappings of these pages may result in any of them to become mapped in multiple locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed and perhaps re-used for other purposes.

Affected configurations

NVD

Node

xenxenRange4.0.0–4.15.0

Node

fedoraprojectfedoraMatch33

fedoraprojectfedoraMatch34

fedoraprojectfedoraMatch35

Node

debiandebian_linuxMatch11.0

CPENameOperatorVersion
xen:xenxenle4.15.0

CPE	Name	Operator	Version
xen:xen	xen	le	4.15.0

CNA Affected

[
  {
    "product": "xen",
    "vendor": "Xen",
    "versions": [
      {
        "status": "affected",
        "version": "xen-unstable"
      }
    ]
  },
  {
    "product": "xen",
    "vendor": "Xen",
    "versions": [
      {
        "lessThan": "4.12",
        "status": "unknown",
        "version": "unspecified",
        "versionType": "custom"
      },
      {
        "lessThan": "unspecified",
        "status": "affected",
        "version": "4.13.x",
        "versionType": "custom"
      },
      {
        "lessThan": "unspecified",
        "status": "unaffected",
        "version": "next of 4.14.x",
        "versionType": "custom"
      }
    ]
  },
  {
    "product": "xen",
    "vendor": "Xen",
    "versions": [
      {
        "lessThan": "4.12",
        "status": "unknown",
        "version": "unspecified",
        "versionType": "custom"
      },
      {
        "lessThan": "unspecified",
        "status": "affected",
        "version": "4.11.x",
        "versionType": "custom"
      },
      {
        "lessThan": "unspecified",
        "status": "unaffected",
        "version": "next of 4.12.x",
        "versionType": "custom"
      }
    ]
  },
  {
    "product": "xen",
    "vendor": "Xen",
    "versions": [
      {
        "status": "affected",
        "version": "4.15.x"
      }
    ]
  }
]