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ubuntucveUbuntu.comUB:CVE-2021-26933
HistoryFeb 17, 2021 - 12:00 a.m.

CVE-2021-26933

2021-02-1700:00:00
ubuntu.com
ubuntu.com
12

5.5 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

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

2.1 Low

CVSS2

Access Vector

LOCAL

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

NONE

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

0.0004 Low

EPSS

Percentile

14.5%

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.

Notes

Author Note
mdeslaur hypervisor packages are in universe. For issues in the hypervisor, add appropriate tags to each section, ex: Tags_xen: universe-binary

5.5 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

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

2.1 Low

CVSS2

Access Vector

LOCAL

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

NONE

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

0.0004 Low

EPSS

Percentile

14.5%