Is CVE-2021-28709 in the CISA KEV catalog?

No. CVE-2021-28709 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-28709?

CVE-2021-28709 has a CVSS v3 base score of 7.8 (HIGH).

What is the EPSS score for CVE-2021-28709?

CVE-2021-28709 has an EPSS score of 0.34% (26th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-28709?

Upgrade xen on debian 11 to 4.14.3+32-g9de3671772-1~deb11u1 or later.

CVE & CISA-KEV Catalog

CVE-2021-28709

HIGH

7.8

CVSS v3

NVD

Description

issues with partially successful P2M updates on x86 T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] x86 HVM and PVH guests may be started in populate-on-demand (PoD) mode, to provide a way for them to later easily have more memory assigned. Guests are permitted to control certain P2M aspects of individual pages via hypercalls. These hypercalls may act on ranges of pages specified via page orders (resulting in a power-of-2 number of pages). In some cases the hypervisor carries out the requests by splitting them into smaller chunks. Error handling in certain PoD cases has been insufficient in that in particular partial success of some operations was not properly accounted for. There are two code paths affected - page removal (CVE-2021-28705) and insertion of new pages (CVE-2021-28709). (We provide one patch which combines the fix to both issues.)

CWE-755

How to fix

Remediation Available

xenDebian

Fixed in:4.14.3+32-g9de3671772-1~deb11u1CVE-2021-28709

Fixed in:4.14.3+32-g9de3671772-1CVE-2021-28709

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.34%probability of exploitation in 30 days

26thpercentile

Low risk: more likely to be exploited than 26% of all known CVEs.

References

Patch1

xenbits.xenproject.org

Third-Party Advisory1

debian.org

Other references3

Related Vulnerabilities

Other CWE-755 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2017-5638	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-7247	Critical	9.8	99%	KEV	Fix
CVE-2023-36933	High	7.5	72%	-	Fix
CVE-2018-0934	High	7.5	66%	-	Fix
CVE-2019-14287	High	8.8	64%	-	Fix
CVE-2019-12815	Critical	9.8	58%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.