CVE-2026-4937

Encrypted-data disclosure via underfilled entropy requests

Published Aug 19, 2026 · Updated Aug 20, 2026

Insufficient entropy in IBM PowerVM Hypervisor firmware allows local users with administrative privileges to decrypt encrypted data. Certain hypervisor calls use less entropy than the caller requests, weakening the cryptographic material used to protect data. Administrative access on the local Power system is required, and the demonstrated consequence is confidentiality loss through decryption rather than data modification or service interruption.

CVSS severity5.3
Medium
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient entropy in IBM PowerVM Hypervisor firmware allows local users with administrative privileges to decrypt encrypted data. Certain hypervisor calls use less entropy than the caller requests, weakening the cryptographic material used to protect data. Administrative access on the local Power system is required, and the demonstrated consequence is confidentiality loss through decryption rather than data modification or service interruption.

The record

CVE
CVE-2026-4937
Published
Aug 19, 2026
Updated
Aug 20, 2026
Vendor
IBM
Product
PowerVM Hypervisor
Classifications
CWE-331, T1140
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record 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=FW1060.00 <=FW1060.71
  2. Affected versionversion=FW1110.00 <=FW1110.20
  3. Affected versionversion=FW950.00 <=FW950.H2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

IBM · PowerVM Hypervisorversion=FW1060.00 <=FW1060.71; version=FW1110.00 <=FW1110.20; version=FW950.00 <=FW950.H2

Published CVSS scores

6.0NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N
5.3IBM CorporationCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-331Insufficient Entropy
T1140Deobfuscate/Decode Files or Information

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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