CVE-2021-28694
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IOMMU page mapping issues on x86 T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to…
rank 22 = 0 + 17 + 0 + 5 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00381 · without this subject the record ranks 22
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 6.8, from NVD · without this subject the record ranks 5
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 22
How much of the world it touches
NVD CPE configurations
4 products in the CPE ranges · without this subject the record ranks 17
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 22
$19,000 = $4.99M incident cost x 1 exposure x 0.00381 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.
Running xen? Check your version
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
What it is stated by the CNA
IOMMU page mapping issues on x86 T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Both AMD and Intel allow ACPI tables to specify regions of memory which should be left untranslated, which typically means these addresses should pass the translation phase unaltered. While these are typically device specific ACPI properties, they can also be specified to apply to a range of devices, or even all devices. On all systems with such regions Xen failed to prevent guests from undoing/replacing such mappings (CVE-2021-28694). receipt
Read the rest of the CNA's description
On AMD systems, where a discontinuous range is specified by firmware, the supposedly-excluded middle range will also be identity-mapped (CVE-2021-28695). Further, on AMD systems, upon de-assigment of a physical device from a guest, the identity mappings would be left in place, allowing a guest continued access to ranges of memory which it shouldn't have access to anymore (CVE-2021-28696).
NVD's analysis a second authority
- severity
- 6.8 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- affected versions
- fedoraproject fedora 33; fedoraproject fedora 34; fedoraproject fedora 35; and 1 more, listed in full below
check it yourself xenbits.xenproject.org openwall.com openwall.com openwall.com lists.fedoraproject.org lists.fedoraproject.org +3 morereceipt
Dated events
Movement the material steps
This score more than doubled inside 72 hours. Both observations are in the full history below.
Show all 30 observations
30 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The full biography
Exploit probability more than doubled between 2021-09-01 and 2021-09-02 (0.00833 → 0.04504) and the record had been public for 4 years, 10 months when this index was last written.
Siblings and hubs
Records related to this one
Fixed with these, by one advisory
advisory-378
Listed because one advisory covers them, not because they are the same defect. Each record's own state is on its own page.
Grouping: held values
Browse the index from here
These are index-wide views, not findings about CVE-2021-28694.
What usually comes next
Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.