Skip to main content

IBM i EUVDEUVD-2026-71485

| CVE-2026-16826 HIGH
OS Command Injection (CWE-78)
2026-09-04 ibm GHSA-q38c-6cwh-cgcx
7.8
CVSS 3.1 · NVD
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain low-privilege local IBM i account
  2. Delivery
    Identify vulnerable command-processing function or utility
  3. Exploit
    Craft input with OS shell metacharacters
  4. Execution
    Submit input to trigger unsanitized system call
  5. Persist
    Execute arbitrary OS commands
  6. Impact
    Achieve full C:H/I:H/A:H system compromise

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization OS command sanitization, avoid shell exec
MITRE ATT&CK

2 techniques across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires a valid local account on the affected IBM i system with sufficient authority to invoke the vulnerable component (PR:L per CVSS vector). The attack vector is strictly local (AV:L), meaning direct network exploitation is not possible; a remote attacker would first need to establish a foothold on the system. No user interaction is required (UI:N) beyond the attacker's own actions. The specific IBM i subsystem, utility, or command interface containing the injection point is not identified in publicly available data, which limits opportunistic exploitation. Exploitation is bounded to IBM i releases 7.3, 7.4, 7.5, and 7.6 and does not affect other IBM platforms. No special non-default configuration is identified as a prerequisite.

Impact

The CVSS 7.8 score is partially offset by the strictly local attack vector (AV:L), which prevents direct remote exploitation without a prior foothold. The EPSS score of 0.12% at the 2nd percentile is notably low, indicating no observed exploitation activity and minimal current threat-actor interest. There is no CISA KEV entry and no known public proof-of-concept. IBM i tends to be deployed in high-security environments such as banking, insurance, and government, where local user access is tightly controlled - further reducing practical risk in well-managed deployments. However, environments hosting multi-tenant IBM i partitions or granting CL or PASE shell access to semi-trusted personnel face the most meaningful exposure, and those operators should treat this as a priority patch cycle item. The combination of low EPSS, local-only vector, and confirmed patch availability places this in the 'patch on next maintenance window' tier rather than emergency remediation.

Exploit ScenarioDerived

A local attacker with a standard IBM i user account supplies crafted input containing OS metacharacters (e.g., a semicolon followed by a privileged command) to the vulnerable IBM i function or utility. The application passes this input unsanitized to an OS command interpreter, executing the injected command under the privileges of the affected process - potentially achieving full system compromise. No public proof-of-concept has been identified, but the low attack complexity (AC:L) means exploitation would be mechanically straightforward once the specific vulnerable call site is located.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.1% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv2 – Sep 08, 2026

OS command injection in IBM i 7.3 through 7.6 allows a local, low-privileged attacker to execute arbitrary operating system commands by supplying specially crafted input containing shell metacharacters that the platform fails to sanitize before passing to an OS command interpreter. The vulnerability (CWE-78) affects IBM's flagship Power Systems operating system across four supported release lines and carries a CVSS 7.8 score reflecting full confidentiality, integrity, and availability impact upon successful exploitation. No public exploit code or CISA KEV listing exists at time of analysis; a vendor-released patch is available via IBM support.

Earlier versions of this analysis (1)
v1 Sep 04, 2026 - 17:40 CVSS 5.3

OS command injection in IBM i versions 7.3 through 7.6 allows local, low-privileged users to execute arbitrary operating system commands due to improper neutralization of special elements in command processing (CWE-78). All four actively supported IBM i release levels are affected, making this broadly relevant across IBM Power Systems environments in financial services, manufacturing, and government sectors. Vendor patch is confirmed available; no public exploit or active exploitation in CISA KEV has been identified at time of analysis.

RemediationAI

Vendor-released patch is available per IBM's support advisory at https://www.ibm.com/support/pages/node/7285844; administrators should consult that page directly to identify the applicable PTF (Program Temporary Fix) or cumulative fix package for their specific IBM i release (7.3, 7.4, 7.5, or 7.6) and apply it during the next maintenance window. As a compensating control where immediate patching is not feasible, restrict local shell access (both PASE and CL command-line) to only fully trusted administrative accounts, and audit IBM i user profiles holding *USE or greater authority over the affected component. Reviewing IBM i audit journal (QAUDJRN) entries for anomalous command strings submitted by low-privileged user profiles can support detection. Note that access restriction is a containment measure, not a fix, and does not eliminate the underlying injection flaw.

Affected VersionsENISA

i 7.6
i 7.5
i 7.4
i 7.3

Affected Packages

euvd i no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

IBM i is IBM's proprietary, integrated operating system for IBM Power Systems hardware (historically marketed as AS/400, iSeries, and System i). CWE-78 (OS Command Injection) arises when user-supplied data containing shell metacharacters - semicolons, pipe operators, backticks, dollar signs, and similar constructs - is concatenated into a string that is passed to a command interpreter (such as PASE shell or CL command processor) without sanitization or proper escaping. The affected CPE (cpe:2.3:a:ibm:i:*:*:*:*:*:*:*:*) covers all sub-versions and fix levels within IBM i 7.3, 7.4, 7.5, and 7.6. The CVSS vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H indicates the vulnerable code path is reachable by a local authenticated user without elevated privileges and without user interaction, and upon exploitation results in full compromise of the vulnerable system. The specific IBM i subsystem, utility, or API containing the injection flaw is not disclosed in available public data.

Know when the next one hits your stack

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

Vendor (ibm) PRIMARY MEDIUM
NVD 7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 7.8 HIGH

Local access with low-privilege account required; once metacharacters are injected into an OS command call, full system compromise across all three impact pillars is achievable.

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 VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

3
Analysis Updated
Sep 08, 2026 - 17:44 vuln.today
v2 - CVSS changed
Severity Changed
Sep 08, 2026 - 17:37 NVD
MEDIUM HIGH
CVSS changed
Sep 08, 2026 - 17:37 NVD
5.3 (MEDIUM) 7.8 (HIGH)

DescriptionNVD

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local attacker to execute arbitrary commands due to improper neutralization of special elements used in an OS command.

Executive ViewAI

Why It Matters

IBM i operating system versions 7.3-7.6 contain a local command injection vulnerability (CWE-78) allowing low-privileged users to execute arbitrary system commands with full impact to confidentiality, integrity, and availability. Organizations operating IBM i on Power Systems should prioritize patching to eliminate insider and compromised-account exploitation risk.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.1%
Top 98% exploitable
Prevalence
Low
niche enterprise OS on IBM Power Systems, not general-purpose
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
High

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

OS command injection occurs when an application passes unsanitized user input directly into system shell commands.

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy