How severe is CVE-2021-28690?

CVE-2021-28690 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-28690 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28690?

CVE-2021-28690 primarily affects Xen. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-28690?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-28690 published?

CVE-2021-28690 was published on 2021-06-29 and last updated on 2026-06-17.

CVE-2021-28690

CVE-2021-28690 is a medium-severity vulnerability in Xen with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Xen
Published: 2021-06-29
Last modified: 2026-06-17

Description

x86: TSX Async Abort protections not restored after S3 This issue relates to the TSX Async Abort speculative security vulnerability. Please see https://xenbits.xen.org/xsa/advisory-305.html for details. Mitigating TAA by disabling TSX (the default and preferred option) requires selecting a non-default setting in MSR_TSX_CTRL. This setting isn't restored after S3 suspend.

Frequently asked questions

What is CVE-2021-28690?: x86: TSX Async Abort protections not restored after S3 This issue relates to the TSX Async Abort speculative security vulnerability. Please see https://xenbits.xen.org/xsa/advisory-305.html for details. Mitigating TAA by disabling TSX (the default and preferred option) requires selecting a non-default setting in MSR_TSX_CTRL. This setting isn't restored after S3 suspend.
How severe is CVE-2021-28690?: CVE-2021-28690 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-28690 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28690?: CVE-2021-28690 primarily affects Xen. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-28690?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-28690 published?: CVE-2021-28690 was published on 2021-06-29 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*
cpe:2.3:o:xen:xen:4.15.0:rc1:*:*:*:*:*:*

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