CVE-2021-38917Network attack vector

Host memory read and write via FSP procedures

Published Dec 10, 2021 · Updated Sep 16, 2024

Arbitrary memory access in IBM PowerVM Hypervisor FW860, FW940, and FW950 allows remote attackers to read and write host memory. IBM has not disclosed which FSP service procedure or validation error permits access outside authorized memory. Exploitation requires service access to the FSP and exposes host confidentiality and integrity without a reported crash or service interruption.

CVSS severity7.4
High
EPSS probability1.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary memory access in IBM PowerVM Hypervisor FW860, FW940, and FW950 allows remote attackers to read and write host memory. IBM has not disclosed which FSP service procedure or validation error permits access outside authorized memory. Exploitation requires service access to the FSP and exposes host confidentiality and integrity without a reported crash or service interruption.

The record

CVE
CVE-2021-38917
Published
Dec 10, 2021
Updated
Sep 16, 2024
Vendor
IBM
Product
PowerVM Hypervisor
Classifications
T1210
Attack vector
network
Privileges
unauthenticated

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=FW860
  2. Affected versionversion=FW940
  3. Affected versionversion=FW950

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · PowerVM Hypervisorversion=FW860; version=FW940; version=FW950

Published CVSS scores

9.4NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:N
7.4IBM CorporationCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1210Exploitation of Remote Services

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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