IBM Power Systems Firmware: Stack-based buffer overflow in service processor mailbox
Summary
IBM Power Systems Firmware FW1060.00 through FW1060.81 contains a stack-based buffer overflow in the service processor (FSP) mailbox interface. An attacker with authenticated service-level access to the FSP can send a crafted mailbox message that overflows host firmware runtime attribute storage and executes arbitrary code in the host firmware runtime. Successful exploitation gives full access to the managed system's memory and hardware interfaces, with high impact on confidentiality, integrity and availability.
Affected
- IBM Power Systems Firmware (PowerVM Hypervisor) FW1060.00 through FW1060.81
- Power 10 systems listed in IBM's bulletin: S1022 (9105-22A), S1024 (9105-42A), S1022s (9105-22B), S1014 (9105-41B), L1022 (9786-22H), L1024 (9786-42H), E1050 (9043-MRX), S1012 (9028-21B)
- Whether other firmware branches or Power 9 systems are affected: Unknown.
Fixed in
- Install FW1060.82 (1060_199) or newer.
Workaround
- No workaround is listed by IBM.
- Interim measure (not confirmed for this CVE): limit Service Processor mailbox access to trusted administrators, enforce strong authentication and review Service Processor logs.
Exploitation
- CVSS 8.2 with vector AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H, so local access with high privileges is required.
- Not listed in CISA KEV. CISA SSVC: exploitation none, not automatable, technical impact total.
- No public exploit code has been confirmed at this time.
Our recommendation
- Check whether you operate Power 10 servers and identify their firmware level.
- Plan the upgrade to FW1060.82 (1060_199) or newer.
- Until patched, restrict FSP and HMC access to a dedicated admin network with strong authentication.
- Monitor Service Processor logs for unusual mailbox activity.
- Verify the affected model list with IBM, as the sources differ on E1050 and S1012.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- IBM Security Bulletin for CVE-2026-96262 www.ibm.com
- OpenCVE: CVE-2026-96262 app.opencve.io
- Strix: CVE-2026-96262 www.strix.ai
- TheHackerWire: CVE-2026-96262 www.thehackerwire.com
- Vulners Rapid7 entry: CVE-2026-96262 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 16:36.
Original description (NVD)
IBM Power Systems Firmware FW1060.00 through FW1060.81 is affected by a vulnerability in the service processor mailbox interface. An attacker with authenticated service-level access to the FSP can send a specially crafted mailbox message to overflow host firmware runtime attribute storage, allowing arbitrary code to be executed in the host firmware runtime. This gives the attacker full access to the managed system's memory and hardware interfaces, resulting in a confidentiality, integrity, and availability impact to the managed system.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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