CVE-2021-38937Network attack vector

System crash via crafted guest hypervisor call

Published Dec 10, 2021 · Updated Sep 16, 2024

Denial of service in IBM PowerVM Hypervisor FW940, FW950, and FW1010 allows remote authenticated users to crash the system. The hypervisor processes a specially crafted call from an IBM-i partition and crashes; IBM has not disclosed the affected routine or validation error. An authenticated IBM-i partition user must submit the call, and the demonstrated consequence is a system crash rather than data access or modification.

CVSS severity6.3
Medium
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in IBM PowerVM Hypervisor FW940, FW950, and FW1010 allows remote authenticated users to crash the system. The hypervisor processes a specially crafted call from an IBM-i partition and crashes; IBM has not disclosed the affected routine or validation error. An authenticated IBM-i partition user must submit the call, and the demonstrated consequence is a system crash rather than data access or modification.

The record

CVE
CVE-2021-38937
Published
Dec 10, 2021
Updated
Sep 16, 2024
Vendor
IBM
Product
PowerVM Hypervisor
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=FW1010
  2. Affected versionversion=FW940
  3. Affected versionversion=FW950

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

IBM · PowerVM Hypervisorversion=FW1010; version=FW940; version=FW950

Published CVSS scores

6.3IBM CorporationCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H
5.5IBM CorporationCVSS:3.0/S:C/C:N/A:H/AC:H/UI:N/PR:L/I:N/AV:N/E:U/RL:O/RC:C
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.8NIST NVDAV:N/AC:L/Au:S/C:N/I:N/A:C

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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