CVE-2026-17100

Host firmware code execution via mailbox out-of-bounds write

Published Aug 19, 2026 · Updated Aug 21, 2026

Out-of-bounds write in IBM Power Systems Firmware allows local users to execute arbitrary code in the host firmware runtime. The service processor mailbox interface writes beyond an intended memory boundary when it processes attacker-controlled mailbox input. Authenticated service-level access to the BMC/FSP is required; successful execution grants full control of the managed system.

CVSS severity8.2
High
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in IBM Power Systems Firmware allows local users to execute arbitrary code in the host firmware runtime. The service processor mailbox interface writes beyond an intended memory boundary when it processes attacker-controlled mailbox input. Authenticated service-level access to the BMC/FSP is required; successful execution grants full control of the managed system.

The record

CVE
CVE-2026-17100
Published
Aug 19, 2026
Updated
Aug 21, 2026
Vendor
IBM
Product
Power Systems Firmware
Classifications
CWE-787, T1068
Attack vector
local
Privileges
admin

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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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
  5. Affected versionversion=OP940.00 <=OP940.81
  6. Affected versionversion=OP940.00 <=OP940.a1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

IBM · Power Systems Firmwareversion=FW1060.00 <=FW1060.80; version=FW1110.00 <=FW1110.30; version=FW1120.00; version=FW950.00 <=FW950.H2; version=OP940.00 <=OP940.81; version=OP940.00 <=OP940.a1

Published CVSS scores

8.2IBM CorporationCVSS: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 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-787Out-of-bounds Write
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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