What is the CVSS score of CVE-2026-16856?

CVE-2026-16856 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of IBM i are affected by CVE-2026-16856?

IBM i 7.5 and 7.6 systems running on IBM Power Systems contain a privilege escalation vulnerability (CVE-2026-16856) that allows local users with low-level credentials to gain complete system…. A patch is available.

How to fix or mitigate CVE-2026-16856?

Within 24 hours, conduct an inventory of all IBM i 7.5 and 7.6 systems deployed on IBM Power Systems hardware and assess which systems are business-critical. Within 7 days, obtain the vendor-released patch from IBM's support portal and deploy it to non-production environments to validate system stability and confirm no application compatibility issues. Within 30 days, complete patch deployment to all production IBM i 7.5 and 7.6 systems beginning with mission-critical systems, and establish monitoring to detect any exploitation attempts targeting this local privilege escalation vector.

IBM i CVE-2026-16856

EUVD-2026-57377 HIGH

OS Command Injection (CWE-78)

2026-08-12 ibm

GHSA-67x9-wvm5-8cxw

Command Injection IBM

8.8

CVSS 3.1 · Vendor: ibm

Severity by source

Vendor (ibm) PRIMARY

8.8 HIGH

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

vuln.today AI

7.8 HIGH

Description specifies 'local attacker,' so AV:L is assessed over the NVD-assigned AV:N; PR:L reflects the required low-privilege account; full C/I/A from privilege escalation to system authority.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (ibm).

CVSS VectorVendor: ibm

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Aug 12, 2026 - 18:44 vuln.today

CVE Published

Aug 12, 2026 - 17:28 nvd

HIGH 8.8

DescriptionCVE.org

IBM i 7.6, and 7.5 could allow a local attacker to gain elevated privileges due to improper neutralization of special elements used in an OS command.

AnalysisAI

OS command injection in IBM i 7.5 and 7.6 enables a local attacker holding low-level credentials to escalate privileges to a highly elevated system authority level by injecting shell metacharacters into an unsanitized OS command interface (CWE-78). Both release streams - 7.5 and 7.6 - running on IBM Power Systems hardware are confirmed affected per the IBM advisory. IBM has released a patch via their support portal; no CISA KEV listing and no public exploit code have been identified at time of analysis.

Technical ContextAI

IBM i (formerly OS/400 and i5/OS) is a proprietary integrated operating system that runs exclusively on IBM Power Systems hardware, predominantly deployed in enterprise workloads in the finance, manufacturing, and retail sectors. CWE-78 (Improper Neutralization of Special Elements used in an OS Command) indicates that one or more IBM i components fail to sanitize user-controlled input before passing it to an OS-level command execution interface, allowing injection of shell metacharacters such as semicolons, pipes, or backticks to chain attacker-supplied commands. The CPE string cpe:2.3:a:ibm:i:*:*:*:*:*:*:*:* covers all IBM i version substrings; the advisory explicitly scopes affected releases to 7.5 and 7.6. Successful injection causes arbitrary OS commands to execute in the context of the vulnerable program, potentially under adopted authority granting *ALLOBJ or *SECADM special authority - effectively full system control.

RemediationAI

Apply the vendor-released patch available from IBM's support portal at https://www.ibm.com/support/pages/node/7283284 for IBM i versions 7.5 and 7.6. The input data confirms patch availability but does not specify an exact PTF (Program Temporary Fix) identifier or cumulative package level, so administrators must consult the advisory page directly to retrieve the correct fix package for their release stream. As a compensating control prior to patching, restrict local and remote interactive login access to only explicitly authorized accounts, and audit all user profiles holding *ALLOBJ, *SECADM, or *JOBCTL special authorities to reduce the pool of accounts that could leverage a successful injection. Reviewing IBM i adopted-authority programs (*PGM objects with USRPRF(*OWNER)) and restricting which user profiles may submit batch jobs can further limit the blast radius. Note that restricting general user accounts may have operational impact in 5250-terminal-dependent workflows and should be coordinated with application owners.