Vulnerability Monitor

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CVE-2021-26933


An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a guest is allowed to control whether memory accesses are bypassing the cache. This means that Xen needs to ensure that all writes (such as the ones during scrubbing) have reached the memory before handing over the page to a guest. Unfortunately, the operation to clean the cache is happening before checking if the page was scrubbed. Therefore there is no guarantee when all the writes will reach the memory.


Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 5.5, requiring local system access to exploit with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts confidentiality (data exposure), for affected systems. Impacting 3 products from xen, from fedoraproject, from debian organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2021-02-17T02:15:13.097

Last Modified

2024-11-21T05:57:04.653

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 5.5 (MEDIUM)

CVSSv2 Vector

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

  • Access Vector: LOCAL
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: PARTIAL
  • Integrity Impact: NONE
  • Availability Impact: NONE
Exploitability Score

3.9

Impact Score

2.9

Weaknesses
  • Type: Primary
    NVD-CWE-noinfo

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System xen xen ≤ 4.14.1 Yes
Operating System fedoraproject fedora 32 Yes
Operating System fedoraproject fedora 33 Yes
Operating System debian debian_linux 10.0 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For xen's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.