CVE-2021-26933

MEDIUM
5.5
CVSS Score
Published: February 17, 2021 at 01:05 AM UTC
Updated: June 17, 2026 at 03:44 AM UTC
3 products affected across 3 vendorsDebian LinuxFedoraXen

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.3%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Xen· Xenwordpress-plugin
95%
4.9.0 ≤ v ≤ 4.14.1

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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