TI-2021-09772 Aliases CVE-2021-28706 GHSA-x89c-76jf-xx4h

Resource allocation without limits in xen

MEDIUM 42CWE-770Published 2021-11-24 · Updated 2024-08-03

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-770.

Summary

guests may exceed their designated memory limit When a guest is permitted to have close to 16TiB of memory, it may be able to issue hypercalls to increase its memory allocation beyond the administrator established limit. This is a result of a calculation done with 32-bit precision, which may overflow. It would then only be the overflowed (and hence small) number which gets compared against the established upper bound.

Why it matters now

EPSS 0.02233 82nd percentileScored 2026-11-07

Fix Fixed xen (Xen): next of 4.15.x

SSVC decision points

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

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Xen	xen	4.12.x	—	No fix listed	CNA
Xen	xen	4.14.x and later	next of 4.15.x	Patch available	CNA
Xen	xen	xen-unstable	—	No fix listed	CNA
Xen	xen	4.13.x	—	No fix listed	CNA

xen VendorXen Affected 4.12.x Fixed in — No fix listed CNA
xen VendorXen Affected 4.14.x and later Fixed in next of 4.15.x Patch available CNA
xen VendorXen Affected xen-unstable Fixed in — No fix listed CNA
xen VendorXen Affected 4.13.x Fixed in — No fix listed CNA

CPE configurations NVD · 4

CPE	Versions	Role	Vendor
cpe:2.3:o:xen:xen::::::::	3.2 to before 4.12	Vulnerable	Xen
cpe:2.3:o:fedoraproject:fedora:34:::::::*	34	Vulnerable	Fedoraproject
cpe:2.3:o:fedoraproject:fedora:35:::::::*	35	Vulnerable	Fedoraproject
cpe:2.3:o:debian:debian_linux:11.0:::::::*	11.0	Vulnerable	Debian

cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:* Versions 3.2 to before 4.12 Vulnerable ·Xen
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian

Remediation

Fix · CNA xen (Xen) Fixed in next of 4.15.x

Fixed in the same release

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

Advisory · 2021-11-21
xen — FEDORA-2021-03645e9807
7 records Highest priority Priority MEDIUM 2 MEDIUM, 5 LOW
Other records, highest priority first
- TI-2021-09774 PoD operations on misaligned GFNs T[his CNA information record relates to multiple CVEs…Priority MEDIUM 40
- TI-2021-09776 Improper privilege management in xenPriority LOW 38
- 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 →
Advisory · 2021-11-24
xen — FEDORA-2021-2b3a2de94f
6 records Highest priority Priority MEDIUM 2 MEDIUM, 4 LOW
Other records, highest priority first
- 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
- TI-2021-09770 PoD operations on misaligned GFNs T[his CNA information record relates to multiple CVEs…Priority LOW 38
Show all 6 records → Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2021-28706
2026-10-03 Alias added: GHSA-x89c-76jf-xx4h

References

Patch 1

https://xenbits.xenproject.org/xsa/advisory-385.txt

Advisory 4

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