CVE-2021-28714

Guest-triggered kernel memory exhaustion

Published Jan 6, 2022 · Updated Aug 3, 2024

Linux kernel xen-netback before 5.15.0 allows local guest users to cause host kernel out-of-memory conditions via crafted RX-ring traffic. The xen-netback backend fails to advance its receive-ring timeout when a packet needs more slots than remain, allowing queued network data to grow without bound. A guest with access to the affected virtual network interface can exhaust memory in the backend domain, typically dom0, interrupting host availability.

CVSS severity6.5
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Linux kernel xen-netback before 5.15.0 allows local guest users to cause host kernel out-of-memory conditions via crafted RX-ring traffic. The xen-netback backend fails to advance its receive-ring timeout when a packet needs more slots than remain, allowing queued network data to grow without bound. A guest with access to the affected virtual network interface can exhaust memory in the backend domain, typically dom0, interrupting host availability.

The record

CVE
CVE-2021-28714
Published
Jan 6, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-770, T1499.002
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 6, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NISTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
2.1NISTAV:L/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.002Endpoint Denial of Service: Service Exhaustion

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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