NVD / CVE Program· CNA XEN

CVE-2021-28702: PCI devices with RMRRs not deassigned correctly Certain PCI devices in a system might be assigned Reserved Memory Regions (specified via Res

Noroxi assessment

Priority: Monitor (action score 30/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.44% (FIRST EPSS).
Physical access to the device is required. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: xen (Alpine:v3.11) 4.13.4-r1; xen (Alpine:v3.13) 4.14.3-r1; xen (Alpine:v3.14) 4.15.1-r1.

Low priority for now. Upgrade to xen (Alpine:v3.11) 4.13.4-r1; xen (Alpine:v3.13) 4.14.3-r1; xen (Alpine:v3.14) 4.15.1-r1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

PCI devices with RMRRs not deassigned correctly Certain PCI devices in a system might be assigned Reserved Memory Regions (specified via Reserved Memory Region Reporting, "RMRR"). These are typically used for platform tasks such as legacy USB emulation. If such a device is passed through to a guest, then on guest shutdown the device is not properly deassigned. The IOMMU configuration for these devices which are not properly deassigned ends up pointing to a freed data structure, including the IO Pagetables. Subsequent DMA or interrupts from the device will have unpredictable behaviour, ranging from IOMMU faults to memory corruption.

HighCVSS 7.6 · v3.1—No exploit Fix available

Published: Oct 6, 2021
Updated: Jun 16, 2026
EPSS: 0.4% · 38th percentile
CWE: CWE-269

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.6 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
xen	xen	cpe:2.3:o:xen:xen
fedoraproject	fedora	cpe:2.3:o:fedoraproject:fedora
debian	debian linux	cpe:2.3:o:debian:debian_linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

debian debian linux9.0
fedoraproject fedora33
fedoraproject fedora34
fedoraproject fedora35
xen xen4.13.0 and later · up to 4.15.1 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (XEN). Independent of NVD's CPE analysis and usually ahead of it.

Xen xen
- unspecified and later · before 4.12unknown
- 4.12.x and later · before unspecifiedaffected
- next of xen-unstable and later · before unspecifiednot affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Alpine:v3.11	xen	from 4.13.0 · before 4.13.4-r1	4.13.4-r1
Alpine:v3.13	xen	from 4.13.0 · before 4.14.3-r1	4.14.3-r1
Alpine:v3.14	xen	from 4.13.0 · before 4.15.1-r1	4.15.1-r1
Debian:11	xen	before 4.14.3+32-g9de3671772-1~deb11u1	4.14.3+32-g9de3671772-1~deb11u1
Debian:12	xen	before 4.14.3+32-g9de3671772-1	4.14.3+32-g9de3671772-1
openSUSE:Leap 15.2	xen	before 4.13.4_02-lp152.2.33.1	4.13.4_02-lp152.2.33.1
openSUSE:Leap 15.3	xen	before 4.14.3_04-3.15.1	4.14.3_04-3.15.1
openSUSE:Tumbleweed	xen	before 4.16.0_01-1.1	4.16.0_01-1.1
SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS	xen	before 4.12.4_16-3.57.1	4.12.4_16-3.57.1
SUSE:Linux Enterprise Module for Basesystem 15 SP2	xen	before 4.13.4_02-3.40.1	4.13.4_02-3.40.1
SUSE:Linux Enterprise Module for Basesystem 15 SP3	xen	before 4.14.3_04-3.15.1	4.14.3_04-3.15.1
SUSE:Linux Enterprise Software Development Kit 12 SP5	xen	before 4.12.4_16-3.55.1	4.12.4_16-3.55.1

Same product

xen: all records

Other highest-scoring records for the same primary product.

CVE-2017-10921The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_host_map mapping, whi
41Plan
CVE-2017-10920The grant-table feature in Xen through 4.8.x mishandles a GNTMAP_device_map and GNTMAP_host_map mapping, when followed by only a GNTMAP_host
41Plan
CVE-2017-10918Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obtain privileged host
41Plan

Published before and after this one in the same product

← EarlierCVE-2021-28700Aug 27, 2021 · xen/arm: No memory limit for dom0less domUs The dom0less feature allows an administrator to create multiple unprivileged domains directly fr
20Monitor
← EarlierCVE-2021-28701Sep 8, 2021 · Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory.
31Monitor
Later →CVE-2021-28710Nov 21, 2021 · certain VT-d IOMMUs may not work in shared page table mode For efficiency reasons, address translation control structures (page tables) may
35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
alpine:xen	4.13.4-r1 · Alpine:v3.11	Package registry (OSV)
debian:xen	4.14.3+32-g9de3671772-1 · Debian:12	Package registry (OSV)
opensuse:xen	4.13.4_02-lp152.2.33.1 · openSUSE:Leap 15.2	Package registry (OSV)
suse:xen	4.12.4_16-3.55.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Physical access to the device is required.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector: Physical
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Changed
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-269 · Improper Privilege Management

CVSS vector

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

nvd-primary

Root cause

To simplify setup, a service account is granted broad, cluster-wide permissions. The principle of least privilege is skipped during installation.

The bug in code

The whole CWE-269 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

yaml

1kind: ClusterRole
2rules:
3  - apiGroups: ["*"]
4    resources: ["*"]
5    verbs: ["*"]

Fixed

yaml

1kind: Role
2metadata:
3  namespace: lodos-system
4rules:
5  - apiGroups: ["apps"]
6    resources: ["deployments"]
7    verbs: ["get", "list", "update"]

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Abuse Elevation Control MechanismT1548

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

For records you follow, these changes also arrive as notifications. →

References

www.openwall.com/lists/oss-security/2021/10/07/2

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records