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IBM PowerVM Hypervisor FW1120.00, FW1110.00 through FW1110.30, and FW1060.00 through FW1060.80 is affected by a vulnerability in host firmware configuration parsing. An attacker with authenticated service-level access to the service processor can write specially crafted configuration data, causing the host firmware boot stack to crash with possible memory corruption during system initialisation, resulting in an integrity and availability impact to the managed system.
The vulnerability stems from improper validation of configuration data processed during the host firmware boot sequence. The service processor (FSP) accepts configuration inputs from authenticated administrative users. Due to insufficient bounds checking, a malicious actor with service-level privileges can supply oversized or malformed configuration parameters. When the host firmware parses this data during system initialisation, a stack-based buffer overflow occurs (CWE-121), corrupting adjacent memory on the call stack. This corrupts the boot stack, leading to a crash or, under specific conditions, arbitrary memory corruption. The vulnerability is triggered early in the boot process, before the hypervisor is fully loaded, making detection and recovery challenging. The attack requires prior compromise of service-level credentials, but once achieved, the impact is severe: the managed system loses integrity and availability. The CVSS v3.1 vector is AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H, yielding a base score of 7.3 (High). IBM has assigned CWE-121 (Stack-based Buffer Overflow) to this weakness.
DailyCVE Form:
Platform: IBM PowerVM Hypervisor
Version: FW1120.00, FW1110.00-FW1110.30, FW1060.00-FW1060.80
Vulnerability: Stack-based Buffer Overflow
Severity: High (7.3 CVSS)
Date: 2026-08-19
Prediction: 2026-08-31
What Undercode Say:
Check current PowerVM firmware version /usr/sbin/lsvpd -v | grep -i firmware Check for vulnerable firmware ranges Vulnerable: FW1120.00, FW1110.00-FW1110.30, FW1060.00-FW1060.80 Query IBM Fix Central for available updates https://www.ibm.com/support/pages/node/7283238 Verify service processor access logs for suspicious configuration writes grep -i "config" /var/log/ras/fsp.log | grep -i "write" Monitor for unexpected host firmware reboots during IPL last reboot | head -20
Exploit: (Educational Purposes!)
- Gain authenticated service-level access to the service processor (FSP) via compromised credentials or HMC access.
- Craft a malicious configuration payload exceeding the expected buffer size for a specific host firmware configuration parameter.
- Write the crafted configuration data to the service processor’s configuration storage.
- Initiate a system IPL (Initial Program Load) or wait for the next scheduled reboot.
- During host firmware boot, the parser copies the oversized parameter into a fixed-size stack buffer without proper bounds checking.
- Stack memory corruption occurs, overwriting the return address or adjacent stack variables, causing the boot stack to crash.
- Successful exploitation leads to denial of service (host crash) or, in some cases, arbitrary code execution within the host firmware context.
Protection:
- Apply IBM security update from Fix Central (IBM Support Page Node 7283238).
- Restrict service processor access to only trusted administrators.
- Enforce multi-factor authentication for HMC and service processor logins.
- Monitor service processor audit logs for unauthorised configuration changes.
- Isolate service processor management networks from general access.
- Regularly review and rotate service processor credentials.
Impact:
- Integrity impact: corruption of host firmware boot stack may allow unauthorised modification of boot-time configuration or memory.
- Availability impact: system crash during initialisation, causing denial of service for the managed system and all hosted partitions.
- No confidentiality impact (C:N).
- Affects multiple IBM Power Systems including S1122, S1124, E1080, S1022, S1024, E1050, E1180, and others.
- Requires authenticated service-level access, limiting attack surface but increasing severity for privileged insiders.
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Sources:
Reported By: nvd.nist.gov
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