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Vulnerability
CVE-2026-17429 is a critical vulnerability in IBM Power Systems Firmware that compromises the security boundary between the Baseboard Management Controller (BMC) or Flexible Service Processor (FSP) and the host system. This architectural flaw allows an attacker with service account or root access to the BMC/FSP to write arbitrary data to hardware control registers, granting full control over the host system and all hosted partitions.
The vulnerability stems from insufficient validation and isolation mechanisms when handling write operations from the BMC or FSP to host processor control registers. In a secure environment, such interfaces enforce strict role-based access controls to prevent unauthorized modification of critical system state variables. However, in affected firmware versions, an attacker who has obtained privileged access to the BMC/FSP can exploit this lack of restriction.
By writing arbitrary data directly to these hardware control registers, an adversary can manipulate fundamental aspects of the host’s operation without triggering standard security alerts or requiring elevated permissions on the main OS kernel. This effectively neutralizes the security benefits of virtualization isolation, as a compromise at the management layer cascades directly into total control over all logical partitions.
The operational impact is comprehensive, affecting confidentiality, integrity, and availability. An attacker could exfiltrate sensitive data, modify critical system files undetected, or crash the system entirely. This vulnerability aligns with CWE-284 (Improper Access Control) and CWE-732 (Operator Permission Assignment Errors), and maps to MITRE ATT&CK techniques related to System Firmware exploitation and Hardware Abstraction Layer manipulation.
DailyCVE Form:
Platform: IBM Power Systems
Version: FW1120.00; FW1110.00-FW1110.30; FW1060.00-FW1060.80; FW950.00-FW950.H2; OP940.00-OP940.a1 (Power9); OP940.00-OP940.81 (Power HMC)
Vulnerability: Incorrect Authorization (CWE-863)
Severity: High (CVSS 8.1)
Date: 2026-08-19
Prediction: Patch expected by 2026-08-26
What Undercode Say:
Analytics
- CVSS v3.1 Vector: `CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:L/I:H/A:H`
– CWE ID: CWE-863 (Incorrect Authorization) - EPSS Score: Not available
- CISA KEV Catalog: Not listed
- Attack Vector: Local (requires BMC/FSP authentication)
- Privileges Required: High (service account or root)
- Scope: Changed (impact affects host system beyond BMC/FSP)
Bash Commands for Version Check:
Check current firmware version on Power Systems lssyscfg -r sys -F name,fwversion Alternative method via HMC lshwres -r sys -F firmware_version Check for vulnerable firmware versions fwversion=$(lssyscfg -r sys -F fwversion | cut -d',' -f2) echo "Current Firmware: $fwversion"
Exploit: (Educational Purposes!)
The exploitation process requires prior compromise of the BMC/FSP service account or root access. Once obtained, the attacker can:
1. Access the BMC/FSP interface via SSH, web interface, or proprietary management protocols
2. Identify hardware control register addresses specific to the Power Systems host processor
3. Craft arbitrary write payloads designed to modify critical system state variables
4. Execute write operations directly to control registers bypassing authorization checks
Conceptual Example:
Connect to BMC/FSP ssh service@<bmc-ip> Identify hardware control registers cat /proc/device-tree/registers Write arbitrary data to control register echo <malicious_value> > /sys/class/register/control Alternatively, use proprietary tool /usr/sbin/register_write --address <reg_addr> --value <payload>
Note: The exact register addresses and write mechanisms are vendor-specific and require deep knowledge of IBM Power Systems hardware architecture.
Protection:
1. Install the latest firmware updates immediately:
- Power 11: Install FW1110.31(1110_134), FW1110.31(1110_155), or FW1120.01(1120_190) or newer
- Power 10: Install FW1060.81(1060_184) or FW1060.81(1060_191) or newer
- Power 9: Install FW950.H3(950_230) or newer
- AC922: Install OP940.a2 or newer
- Power HMC: Install OP940.82 or newer
- Restrict BMC/FSP access to only authorized administrators using network segmentation and firewall rules.
- Enable comprehensive logging and monitoring of all BMC/FSP access and hardware register modification attempts.
- Implement multi-factor authentication for all BMC/FSP administrative interfaces.
- Regularly audit service account usage and revoke unnecessary privileges.
Impact:
- Confidentiality: Attackers can exfiltrate sensitive data from memory or storage
- Integrity: Critical system files and configurations can be modified without detection
- Availability: Systems can be crashed, services halted, or hardware rendered unresponsive
- Virtualization Isolation: Complete compromise of all logical partitions hosted on the physical hardware
- Persistence: Firmware-level access makes detection difficult for standard OS-level security solutions
- Supply Chain Risk: Affects multiple IBM Power Systems models including E1080, S1022, S922, H922, E950, AC922, and Power HMC
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Sources:
Reported By: nvd.nist.gov
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