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TI-2021-09776 Aliases CVE-2021-28710GHSA-ccqw-rpfw-2m25

Improper privilege management in xen

Priority LOW 38CWE-269Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Privilege escalation
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-269.

Summary

certain VT-d IOMMUs may not work in shared page table mode For efficiency reasons, address translation control structures (page tables) may (and, on suitable hardware, by default will) be shared between CPUs, for second-level translation (EPT), and IOMMUs. These page tables are presently set up to always be 4 levels deep. However, an IOMMU may require the use of just 3 page table levels. In such a configuration the lop level table needs to be stripped before inserting the root table's address into the hardware pagetable base register. When sharing page tables, Xen erroneously skipped this stripping. Consequently, the guest is able to write to leaf page table entries.

Why it matters now

EPSS 0.00285 21st percentileScored 2026-11-07
Fix Fixed xen (Xen): next of xen-unstable

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
Xenxen4.15.x and laternext of xen-unstablePatch availableCNA
  • xen VendorXen Affected 4.15.x and later Fixed in next of xen-unstable Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:xen:xen:4.15.0:*:*:*:*:*:x86:*4.15.0VulnerableXen
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
  • cpe:2.3:o:xen:xen:4.15.0:*:*:*:*:*:x86:* Versions 4.15.0 Vulnerable ·Xen
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject

Remediation

  • Fix · CNA xen (Xen) Fixed in next of xen-unstable

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    xen — FEDORA-2021-03645e9807

    7 records Highest priority Priority MEDIUM 2 MEDIUM, 5 LOW

    Other records, highest priority first

    • TI-2021-09772 Resource allocation without limits in xenPriority MEDIUM 42
    • TI-2021-09774 PoD operations on misaligned GFNs T[his CNA information record relates to multiple CVEs…Priority MEDIUM 40
    • TI-2021-09773 PoD operations on misaligned GFNs T[his CNA information record relates to multiple CVEs…Priority LOW 38
    Show all 7 records → Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-28710
  2. 2026-10-03 Alias added: GHSA-ccqw-rpfw-2m25

References

Advisory 3

  • TI-2012-00210 The x86-64 kernel system-call functionality in Xen 4.1.2 and earlier, as used in Citrix… CVSS 2.0HIGH 7.2
  • TI-2023-07042 Information disclosure through error messages in AMD Ryzen™ 3000 Series Desktop… CVSS 3.1MEDIUM 5.5
  • TI-2015-04333 The C+ mode offload emulation in the RTL8139 network card device model in QEMU, as used… CVSS 2.0HIGH 9.3
  • TI-2015-06741 The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows… CVSS 3.1CRITICAL 10.0
  • TI-2018-06436 A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures… CVSS 3.0HIGH 7.8
  • TI-2024-20522 x86: Incorrect logic for BTC/SRSO mitigations CVSS 3.1HIGH 7.5
See all 489 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences