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Fencer Vulns
high 7.6

CVE-2021-28702 json

PCI devices with RMRRs not deassigned correctly Certain PCI devices in a system might be assigned Reserved Memory Regions (specified via Re…

published 2021-10-06 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-15359

cvss
7.6
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

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.

Patch / fix

  • xen Debian 14, Debian 13, Debian 12 4.14.3+32-g9de3671772-1

debian advisories DEBIAN-CVE-2021-28702

  • xen SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +3 more 4.12.4_16-3.57.1
  • xen SLE Module for Server Applications 15 SP3, SLE Module for Basesystem 15 SP3, SLE Micro 5.1 4.14.3_04-3.15.1
  • xen SLE Module for Server Applications 15 SP2, SLE Module for Basesystem 15 SP2, SLE Micro 5.0 4.13.4_02-3.40.1
  • xen SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 4.12.4_16-3.55.1

suse advisories SUSE-SU-2021:3977-1SUSE-SU-2021:3968-1SUSE-SU-2021:3888-1SUSE-SU-2021:3852-1

  • xen openSUSE Tumbleweed 4.16.0_01-1.1
  • xen openSUSE Leap 15.3 4.14.3_04-3.15.1
  • xen openSUSE Leap 15.2 4.13.4_02-lp152.2.33.1

opensuse advisories openSUSE-SU-2024:11624-1openSUSE-SU-2021:3968-1openSUSE-SU-2021:1543-1

  • xen Alpine 3.12, Alpine 3.11 4.13.4-r1
  • xen Alpine 3.13 4.14.3-r1
  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 4.15.1-r1

alpine advisories ALPINE-CVE-2021-28702

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-28702 updated cvss 4.0

xen: administrators of guests which have been assigned RMRR-using PCI devices can cause DoS

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.6 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Xen xen

Classification

Weakness
  • CWE-269 Improper Privilege Management

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.