Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:A) | Adjacent network |
| Attack complexity (AC:H) | High complexity |
| Privileges required (PR:N) | No privileges required |
| User interaction (UI:N) | No user interaction |
| Scope (S:U) | Scope unchanged |
| Confidentiality (C:H) | High confidentiality impact |
| Integrity (I:H) | High integrity impact |
| Availability (A:H) | High availability impact |
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
About Ibm Power System S1122 (9824-22a) Firmware
CVE-2026-18821 affects Ibm Power System S1122 (9824-22a) Firmware, a product from Ibm. Before acting, confirm where Ibm Power System S1122 (9824-22a) Firmware runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: IBM PowerVM Hypervisor FW1120.00, FW1110.00 through FW1110.30, FW1060.00 through FW1060.80, and FW950.00 through FW950.H2 Power Systems Firmware is affected by a vulnerability in partition firmware during network boot. An unauthenticated attacker on the same network as a partition undergoing network boot can send a malformed packet, allowing arbitrary code to be executed in the partition firmware and compromising everything subsequently loaded by that partition. Other partitions and the managed system are not affected. Only partitions actively performing a network boot are affected, resulting in a confidentiality, integrity, and availability impact.
The weakness class is Out of Bounds Write. The program writes past the end of a buffer, a common path to code execution.
Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Ibm Power System S1122 (9824-22a) Firmware |
| Affected versions | Power System S1122 (9824-22a) Firmware from fw1110.00 before fw1110.31; Power System S1122 (9824-22a) Firmware fw1120.00; Power System S1124 (9824-42a) Firmware from fw1110.00 before fw1110.31; Power System S1124 (9824-42a) Firmware fw1120.00; Power System S1122s (9824-22b) Firmware from fw1110.00 before fw1110.31; Power System S1122s (9824-22b) Firmware fw1120.00; Power System S1114 (9824-41b) Firmware from fw1110.00 before fw1110.31; Power System S1114 (9824-41b) Firmware fw1120.00; Power System L1122 (9856-22h) Firmware from fw1110.00 before fw1110.31; Power System L1122 (9856-22h) Firmware fw1120.00; Power System L1124 (9856-42h) Firmware from fw1110.00 before fw1110.31; Power System L1124 (9856-42h) Firmware fw1120.00 |
| Published | Aug 19, 2026 |
| Last modified | Aug 25, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | psirt@us.ibm.com |
How to detect it
- Inventory every instance of Ibm Power System S1122 (9824-22a) Firmware and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Ibm Power System S1122 (9824-22a) Firmware named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Ibm Power System S1122 (9824-22a) Firmware to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-787: Out of Bounds Write More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
IBM DataStage on Cloud Pak for Data 5.4.0.0 can allow a man-in-the-middle attacker to present a forged TLS certificate, intercept the connection, and capture the IAM bearer Authorization header automatically attached by the session adapter. The captured token grants full platform-scope tenant API access, enabling the attacker to read and manipulate the victim's DataStage projects, flows, assets, and pipeline definitions. This is client-side SDK code running on the user's own machine, so exploitation requires an external network interceptor rather than a co-tenant in the shared cluster.
IBM DataStage on Cloud Pak for Data 5.4.0.0 could allow a remote authenticated attacker to execute arbitrary code due to improper validation of pathname during a path traversal.
IBM DataStage on Cloud Pak for Data 5.4.0.0 could allow a remote authenticated attacker to execute arbitrary code due to improper neutralization of special elements used in an OS command.
IBM DataStage on Cloud Pak for Data 5.4.0.0 could allow a remote authenticated attacker to cause a denial of service due to a path traversal vulnerability.
IBM DataStage on Cloud Pak for Data 5.4.0.0 could allow a remote authenticated attacker to execute arbitrary commands due to improper neutralization of special elements used in an OS command.
IBM Guardium Data Protection 12.0, 12.1, and 12.2 could allow a remote attacker to execute arbitrary code due to a buffer overflow.
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2026-18821 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications