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TI-2026-71804 Aliases CVE-2026-79610GHSA-mm4r-fcq9-pfr4

Race condition in Xen grant table version changes

Priority LOW 39CWE-362Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.

Summary

Xen's grant table code can free and reallocate status pages when a guest switches grant table versions from v2 to v1 and back to v2, leaving pointers calculated earlier into the status array stale (CWE-362). A local attacker with low privileges can trigger this race condition, with high impact to confidentiality, integrity and availability.

Written with Claude Haiku 5.5 from the sources below · 2026-10-27

Description from the CNA

XSA-501 was about issues with v1 -> v2 and v2 -> v1 changes racing certain other grant table operations. Sadly a v2 -> v1 -> v2 change has yet another effect which wasn't accounted for: During the first change, status pages would be freed. During the second change they would be allocated again. Hence across the full pair of change the addresses of the status pages may change, rendering stale previously calculated pointers into the status array.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00148 3rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
XenXen——No fix listedCNA
  • Xen VendorXen Affected — Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for Xen.

Written with Claude Haiku 5.5 from the sources below · 2026-10-27

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-79610
  2. 2026-10-13 Alias added: GHSA-mm4r-fcq9-pfr4
  3. 2026-10-20 CVSS score added · CISA ADP
  4. 2026-10-20 Weakness changed · CISA ADP
  5. 2026-10-20 CISA SSVC decision points changed
  6. 2026-10-23 Affected versions changed · Red Hat
  7. 2026-10-23 CVSS score added · Red Hat

References

Other 1

  • 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 541 →

Sources

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