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7.0
HIGH CVSS 3.1
CVE-2021-28703
Xen Grant Table V2 Status Page Memory Access Control Vulnerability (Double Access)
Description

grant table v2 status pages may remain accessible after de-allocation (take two) 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. This bug was fortuitously fixed by code cleanup in Xen 4.14, and backported to security-supported Xen branches as a prerequisite of the fix for XSA-378.

INFO

Published Date :

Dec. 7, 2021, 12:15 p.m.

Last Modified :

Nov. 21, 2024, 6 a.m.

Remotely Exploit :

No

Source :

[email protected]
Affected Products

The following products are affected by CVE-2021-28703 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Xen xen
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 MEDIUM [email protected]
CVSS 3.1 HIGH [email protected]
Solution
This information is provided by the 3rd party feeds.
  • All Xen users should upgrade to the latest version: # emerge --sync # emerge --ask --oneshot --verbose >=app-emulation/xen-4.16.6_pre1
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-28703.

URL Resource
https://security.gentoo.org/glsa/202402-07
https://xenbits.xenproject.org/xsa/advisory-387.txt Vendor Advisory
https://security.gentoo.org/glsa/202402-07
https://xenbits.xenproject.org/xsa/advisory-387.txt Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-28703 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-28703 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-28703 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2021-28703 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://security.gentoo.org/glsa/202402-07
    Added Reference https://xenbits.xenproject.org/xsa/advisory-387.txt
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Feb. 04, 2024

    Action Type Old Value New Value
    Added Reference Xen Project https://security.gentoo.org/glsa/202402-07 [No types assigned]
  • Initial Analysis by [email protected]

    Dec. 09, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:L/AC:M/Au:N/C:C/I:C/A:C)
    Added CVSS V3.1 NIST AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
    Changed Reference Type https://xenbits.xenproject.org/xsa/advisory-387.txt No Types Assigned https://xenbits.xenproject.org/xsa/advisory-387.txt Vendor Advisory
    Added CWE NIST NVD-CWE-Other
    Added CPE Configuration OR *cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:* versions up to (excluding) 14.4
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 7
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 6.9
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.11 }} 0.01%

score

0.30707

percentile