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CVE-2026-17195 is a memory corruption vulnerability affecting IBM AIX versions 7.2 and 7.3, as well as IBM PowerVM Virtual I/O Server (VIOS) version 4.1. The flaw resides in the operating system’s failure to properly validate memory boundaries during write operations, classified under CWE-787: Out-of-bounds Write.
This vulnerability allows a local attacker to write data outside the intended buffer or array structure. In the context of operating systems and virtualization layers like AIX and PowerVM VIOS, such errors are particularly dangerous because they can corrupt critical system structures, leading to unpredictable behavior ranging from application crashes to complete kernel panics. The presence of this flaw indicates a failure in boundary checking mechanisms within the affected components, allowing data intended for one memory region to overwrite adjacent areas that may contain control flow information or other sensitive operational data.
From an attacker perspective, this vulnerability is exploitable by local users who have already gained access to the system environment. Unlike remote code execution vulnerabilities that can be triggered over a network without authentication, out-of-bounds write issues in operating systems typically require the adversary to possess valid credentials and interact with specific services or processes running on the host machine. The primary impact of exploiting this flaw is a denial of service condition. By triggering the memory corruption through crafted inputs or sequences of operations, an attacker can cause the affected system component to crash, thereby disrupting availability for legitimate users and potentially taking down critical infrastructure services hosted on that hardware.
While out-of-bounds writes can sometimes lead to arbitrary code execution if specific conditions are met, such as overwriting function pointers with controlled data, the reported impact focuses on stability disruption rather than privilege escalation or remote command injection in this specific instance. The vulnerability aligns closely with Common Weakness Enumeration (CWE) category CWE-787: Out-of-bounds Write, which describes situations where a write operation targets memory outside of the allocated buffer boundaries. It also relates to CWE-120: Buffer Overflow, specifically when the overflow results in writing beyond the end of the destination buffer.
DailyCVE Form:
Platform: IBM AIX / PowerVM VIOS
Version: 7.2, 7.3 / 4.1
Vulnerability: Out-of-bounds Write
Severity: Medium (6.5)
date: August 20, 2026
Prediction: August 14, 2026 (APAR availability)
What Undercode Say:
Check AIX version and VIOS level:
oslevel -s ioslevel
Check if system is vulnerable by reviewing APAR status:
instfix -i | grep -i "IJ59566|IJ59565|IJ59564|IJ59563"
Verify running processes and memory usage to detect potential crash indicators:
ps -ef | grep -E "vios|aix" svmon -G
Monitor system logs for out-of-bounds write related crashes:
errpt -a | grep -i "memory|corrupt|write"
Exploit: (Educational Purposes!)
A local attacker with valid credentials could craft malicious input or execute a sequence of operations that triggers the out-of-bounds write. The exact exploitation vector is not publicly disclosed, but it typically involves interacting with a vulnerable system call or service that fails to validate buffer sizes. Attackers may attempt to overflow adjacent memory regions to cause a system crash (DoS). No public exploit code is currently available.
Protection:
Apply the following fixes from IBM Fix Central:
| AIX Level | Service Pack | APAR |
||||
| AIX 7.3 TL04 | SP2 | IJ59563 |
| AIX 7.3 TL03 | SP3 | IJ59564 |
| AIX 7.3 TL02 | SP5 | IJ59565 |
| AIX 7.2 TL05 | SP13 | IJ59566 |
| VIOS Level | Fix Pack | APAR |
||||
| VIOS 4.1.2 | 4.1.2.20 | IJ59563 |
| VIOS 4.1.1 | 4.1.1.30 | IJ59564 |
| VIOS 4.1.0 | 4.1.0.50 | IJ59565 |
An LPAR reboot is required to complete the SP/FP update. On AIX, Live Update can be used to avoid a reboot. Implement least-privilege access controls to limit which local users can execute code or interact with vulnerable system components.
Impact:
Successful exploitation leads to a denial of service condition, causing the affected system component to crash and disrupting availability for legitimate users. This can potentially take down critical infrastructure services hosted on the hardware. The CVSS v3.1 vector is AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H, with a base score of 6.5 (Medium).
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Sources:
Reported By: nvd.nist.gov
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