CVE-2026-16707

Managed-system compromise via out-of-bounds mailbox access

Published Aug 19, 2026 · Updated Aug 21, 2026

IBM PowerVM Hypervisor before FW1120.01, FW1110.31, FW1060.81, and FW950.H3 allows attackers to tamper with host firmware via mailbox messages. The service processor mailbox interface accepts a specially crafted message from an authenticated FSP service context and uses it to read or modify arbitrary Hostboot memory regions outside intended bounds. Exploitation requires authenticated service-level access to the flexible service processor and can subvert the host firmware boot stack and the hypervisor loaded after it.

CVSS severity8.2
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

IBM PowerVM Hypervisor before FW1120.01, FW1110.31, FW1060.81, and FW950.H3 allows attackers to tamper with host firmware via mailbox messages. The service processor mailbox interface accepts a specially crafted message from an authenticated FSP service context and uses it to read or modify arbitrary Hostboot memory regions outside intended bounds. Exploitation requires authenticated service-level access to the flexible service processor and can subvert the host firmware boot stack and the hypervisor loaded after it.

The record

CVE
CVE-2026-16707
Published
Aug 19, 2026
Updated
Aug 21, 2026
Vendor
OpenBMC Project
Product
PowerVM Hypervisor
Classifications
CWE-125, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 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 <=FW1060.80
  2. Affected versionversion=FW1110.00 <=FW1110.30
  3. Affected versionversion=FW1120.00
  4. Affected versionversion=FW950.00 <=FW950.H2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

OpenBMC Project · PowerVM Hypervisorversion=FW1060.00 <=FW1060.80; version=FW1110.00 <=FW1110.30; version=FW1120.00; version=FW950.00 <=FW950.H2

Published CVSS scores

8.2IBMCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1068Exploitation for Privilege Escalation

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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