EUVD-2026-62826
GHSA-mfcf-ph4g-vj2m
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessReach exposed AIX/VIOS service
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DeliverySend crafted network request
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ExploitOverflow stack buffer (CWE-787)
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ExecutionOverwrite saved return address
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PersistExecute arbitrary code on host
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ImpactFull system compromise
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Per the CVSS vector (AV:N/AC:L/PR:N/UI:N), no authentication and no user interaction are required, and attack complexity is low - remote unauthenticated exploitation is possible against affected IBM AIX 7.2/7.3 and PowerVM VIOS 4.1 hosts. The concrete precondition is network reachability of the vulnerable (but publicly unnamed) service, so exploitation is limited by whether that component is exposed to the attacker; hosts on isolated/segmented management networks or behind restrictive ACLs are substantially harder to reach. Exploitation is further constrained to the IBM Power/AIX platform, meaning any working exploit must target the Power architecture and the specific affected releases (AIX 7.2/7.3, VIOS 4.1). |
| Impact | This rates as a genuine high priority rather than an inflated high-CVSS score: the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N) describes unauthenticated, low-complexity, network-reachable exploitation with full C/I/A impact, which is the worst-case profile for a server OS. Any organization running exposed AIX or VIOS instances should treat this as urgent and prioritize patching. Countervailing signals temper the raw score: there is no EPSS value, KEV status, or SSVC decision data in the provided intelligence, and no public proof-of-concept is referenced, so widespread automated exploitation is not yet demonstrated. The primary uncertainty is that IBM has not publicly disclosed which service is affected or the precise preconditions, so the true remote-reachability depends on whether the vulnerable component is network-exposed by default - verify with the IBM advisory before assuming internet-facing risk. In short, the impact ceiling is maximal and the theoretical accessibility is high, but confirmed in-the-wild activity is currently absent. |
| Exploit ScenarioDerived | An attacker with network access to an exposed AIX or VIOS host sends a crafted request to the vulnerable network-facing service, overflowing a stack buffer and overwriting the saved return address to hijack execution. Given AV:N/AC:L/PR:N/UI:N, this requires neither credentials nor user interaction, and successful exploitation grants code execution with the privileges of the affected service - potentially full host compromise. No public proof-of-concept is currently referenced. |
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Alert meAnalysisAIv1 – Aug 19, 2026
Remote code execution in IBM AIX 7.2/7.3 and PowerVM VIOS 4.1 stems from a stack-based buffer overflow that a network-based attacker can trigger without authentication or user interaction, per the CVSS 9.8 vector. Successful exploitation yields full compromise (high confidentiality, integrity, and availability impact) of Unix systems that frequently underpin enterprise and mission-critical workloads. No public exploit identified at time of analysis, and the CVE is not currently listed in CISA KEV.
RemediationAI
Apply the fixes referenced in IBM's advisory at https://www.ibm.com/support/pages/node/7283858 - IBM typically distributes AIX and VIOS corrections as APARs and interim fixes (ifixes) mapped to specific technology levels and service packs; no single fixed version string was provided in this intelligence, so consult that advisory for the exact ifix/APAR per your TL/SP and install it (Patch available per vendor advisory). Until fixes are deployed, reduce exposure by restricting network reachability of AIX and VIOS management and service ports to trusted administrative networks (segment VIOS/HMC management LANs, apply firewall/ACL filtering), which limits the unauthenticated network vector at the cost of tighter operational access; avoid exposing AIX or VIOS services directly to untrusted or internet-facing networks. Because the exact vulnerable service is not publicly named, prioritize network-level containment and monitoring of the affected hosts rather than disabling a single feature until IBM's advisory identifies the component.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 2 packages in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The flaw is classified as CWE-787 (Out-of-bounds Write), realized here as a stack buffer overflow in IBM's AIX operating system and the PowerVM Virtual I/O Server (VIOS), which brokers storage and network I/O for LPARs on IBM Power hardware. A stack overflow overwrites adjacent stack memory - including saved return addresses - which on an unmitigated code path can redirect control flow to attacker-controlled instructions. IBM's advisory (support node 7283858) does not publicly name the exact vulnerable service or network daemon, but the network attack vector implies a listening component reachable over the network parses attacker-supplied input without adequate bounds checking. AIX and VIOS run on the Power ISA, so any weaponization would be architecture-specific.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Description states remote attacker and stack overflow enabling code execution with no stated auth or interaction, so AV:N/AC:L/PR:N/UI:N with full C/I/A impact.
Primary rating from Vendor (us).
CVSS VectorVendor: us
DescriptionCVE.org
IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a remote attacker to execute arbitrary code due to a stack buffer overflow.
Executive ViewAI
CVE-2026-16894 is a critical remote code execution vulnerability in IBM AIX 7.2/7.3 and PowerVM VIOS 4.1 that permits unauthenticated network attackers to achieve complete system compromise, affecting enterprise Unix infrastructure that typically hosts mission-critical applications and sensitive data. With no vendor patch currently available, this vulnerability poses immediate and sustained risk to production environments. Organizations running affected systems face potential data breach, operational disruption, and loss of system availability without urgent interim controls.
No vendor-released patch identified at time of analysis. Interim mitigations include: network segmentation and firewall rules restricting unauthenticated connections to affected AIX 7.2/7.3 and VIOS 4.1 systems; enhanced monitoring and logging of network access attempts and system-level anomalies; air-gapping or offline isolation of non-critical affected systems where operationally feasible; and deployment of intrusion detection signatures targeting stack overflow exploitation vectors as available from security vendors.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
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OS command injection in IBM AIX 7.2 and 7.3 and PowerVM VIOS 4.1 lets a remote, low-privileged authenticated attacker ru
OS command injection in IBM AIX 7.2 and 7.3 and in IBM PowerVM VIOS 4.1 lets a remote, authenticated attacker execute ar
OS command injection in IBM AIX 7.2/7.3 and PowerVM VIOS 4.1 lets a remote authenticated attacker run arbitrary commands
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