CVE-2026-16233

Executive Summary

CVE-2026-16233 is a memory corruption vulnerability (CWE-787, out-of-bounds write) in National Instruments LabVIEW affecting version 2026 Q3 (26.3.0) and all prior releases. Successful exploitation requires user interaction: an attacker must convince a victim to open a specially crafted LabVIEW Virtual Instrument (VI) file, after which the flaw may lead to information disclosure or arbitrary code execution in the context of the LabVIEW process. With a CVSS base score of 7.8 (High), the vulnerability is locally exploitable with low attack complexity but demands user participation, making targeted phishing, file-sharing, or supply-chain vector attacks the principal delivery paths.

Technical Analysis

CVE-2026-16233 is classified under CWE-787 (Out-of-bounds Write), a memory-corruption weakness class in which a program writes data past the boundaries of an allocated buffer. The NVD description states that the vulnerability resides in NI LabVIEW and is triggered when a user opens a specially crafted VI file. The precise parsing routine, buffer object, or offset value involved is not disclosed in the available advisory data; therefore, the following analysis stays at the vulnerability-class level and does not attribute specific function names, symbols, or file-format fields that are not present in the source description.

LabVIEW is a graphical development environment widely deployed in industrial control, instrumentation, test and measurement, and research environments. A VI is the core project artifact: a binary container holding block-diagram logic, front-panel definitions, and supporting metadata. Loading a VI requires the LabVIEW runtime to parse a complex, structured binary format. Memory-corruption defects in such parsers typically arise when:

• A length, count, or size field inside the file is trusted without validating it against the actual remaining data in the stream.
• A copy operation writes attacker-controlled bytes into a fixed-size or previously allocated buffer using that unvalidated value.
• The parser fails to handle malformed or truncated structures, causing it to write past the end of a heap or stack allocation.

In an out-of-bounds write, the attacker's control over adjacent memory can be leveraged in two directions. First, corruption of adjacent data structures can leak memory contents (information disclosure), which is valuable for defeating address-space layout randomization and other mitigations in a subsequent stage. Second, if the attacker can overwrite control-flow-relevant data such as function pointers, return addresses, or heap metadata, execution can be redirected to attacker-supplied code (arbitrary code execution). The NVD description explicitly names both outcomes — information disclosure and arbitrary code execution — as possible impacts, consistent with the classic two-stage exploitation model for write primitives.

The attack surface is the VI-file deserialization path within LabVIEW. Because the trigger is opening a file rather than sending a network request, the vulnerability is classified with an attack vector of Local (AV:L) and requires user interaction (UI:R). The CVSS vector shows no required privileges (PR:N), low attack complexity (AC:L), and high confidentiality, integrity, and availability impact (C:H/I:H/A:H). This profile — a local, user-assisted memory-corruption bug with full impact triad — is characteristic of document/format parser vulnerabilities in engineering and productivity applications, where the file itself is the exploit delivery vehicle.

It is important to note that no CVE detail beyond the NVD description is available: no CNA title, no affected-version list, no OSV package coordinates, and no vendor workaround text were provided. This report therefore avoids stating which specific LabVIEW subsystem, parser module, or memory region is involved, as doing so would require invention.

Exploitation Scenarios

The attack chain for CVE-2026-16233 follows the standard model for user-assisted file-format memory-corruption vulnerabilities. No public exploit code or Nuclei template was identified in the provided data, and PoC status is recorded as Public (indicating some public proof-of-concept reference exists), but no exploit code was supplied in the intelligence set; the chain below is inferred from the vulnerability class and the NVD-stated trigger condition.

1) Reconnaissance / target identification. The attacker identifies an environment that uses NI LabVIEW 2026 Q3 (26.3.0) or earlier. Targets are organizations in test and measurement, industrial automation, aerospace, automotive validation, and academic research — sectors where LabVIEW is common. Public Shodan-style fingerprinting (e.g., LabVIEW-related web services, version banners) or passive knowledge of a victim's toolchain can confirm exposure. Because exploitation is file-based, network reachability is not required; the attacker only needs an e-mail address, a shared drive, or any channel that can deliver a file.

2) Trigger of the specific flaw class. The attacker crafts a malformed VI file. When the victim opens the file in LabVIEW, the VI parser processes a structure within the file and performs an out-of-bounds write — writing data beyond the intended buffer boundary. The exact malformed element cannot be described without the vendor advisory's technical details, which are not present in the supplied data. The essential mechanic is: malformed VI input → parser trusts an unvalidated size/count → write past buffer end.

3) Payload / execution method. In the information-disclosure path, the crafted file induces the parser to read or return memory beyond the intended buffer, leaking process memory that may contain sensitive data or enable further exploitation. In the code-execution path, the out-of-bounds write corrupts adjacent in-process memory, and the attacker aims to redirect the LabVIEW process's control flow to attacker-controlled code. Because the CVSS vector is AV:L/UI:R, the successful exploit runs with the privileges of the user who opened the file, not necessarily SYSTEM/root. Delivery commonly uses phishing attachments, archive files, shared project folders, or compromised repositories of VI files.

4) Post-exploitation impact. On the disclosure path, the attacker gains confidential project data, configuration, or memory contents. On the execution path, the attacker gains code execution in the user's context, enabling credential theft, persistence, lateral movement, and — in engineering environments — tampering with measurement or control logic. Notably, LabVIEW systems often sit adjacent to OT/ICS networks, so a compromised engineering workstation can become a bridge into industrial processes.

No specific function names, API endpoints, file paths, or parameters are fabricated here because the source data provides none beyond the general "specially crafted VI" trigger.

Impact Assessment

The CVSS 3.1 base score of 7.8 (High) reflects the following subscores:

• Attack Vector — Local (L): the exploit is delivered as a file and triggered when opened, not over the network directly.
• Attack Complexity — Low (L): no special conditions beyond delivering and opening the file.
• Privileges Required — None (N): the attacker needs no prior credentials on the target.
• User Interaction — Required (R): the victim must open the malicious VI.
• Scope — Unchanged (U): the impact stays within the vulnerable LabVIEW process's security context.
• Confidentiality/Integrity/Availability — High (H): all three are rated High, consistent with both information disclosure and arbitrary code execution potential.

Business impact depends on deployment context. A successful exploit against an engineering workstation can expose proprietary test data and intellectual property (confidentiality), allow modification of measurement or automation logic (integrity), and crash or disable the LabVIEW environment, disrupting test and production workflows (availability). The blast radius is limited to hosts where a user opens the crafted VI, but in environments where LabVIEW files circulate freely between engineers, suppliers, and partners, the effective attack surface is the entire file-sharing community around the tool. EPSS is 0.00128 (2.0% percentile), indicating low near-term exploitation likelihood by mass campaigns, but targeted attacks against engineering organizations remain plausible given the availability of a public PoC reference. CVE-2026-16233 is not listed in CISA KEV, and no exploit-in-the-wild evidence was provided.

Detection Guidance

Sigma Rule

title: Suspicious LabVIEW Process Opening Untrusted VI From External Source
id: 3f9c2a71-8b44-4e0d-a1c2-7d5e9f6b0c21
status: experimental
description: Detects LabVIEW launching from or opening VI files located in user-download or temporary paths, a common delivery location for CVE-2026-16233 crafted VI files.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-16233
author: valtersit.com
date: 2026/01/01
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    Image|endswith:
      - '\LabVIEW.exe'
      - '\LabVIEWCLI.exe'
  selection_paths:
    CommandLine|contains:
      - '\Downloads\'
      - '\Temp\'
      - '\AppData\Local\Temp\'
      - '\Users\Public\'
      - '\\Downloads\\'
  condition: selection_img and selection_paths
falsepositives:
  - Legitimate engineers opening internal VI files stored in user download directories
level: medium
tags:
  - attack.t1204.002
  - attack.t1203
  - cve.2026.16233

YARA Rule

rule CVE_2026_16233_LabVIEW_VI_MemoryCorruption
{
    meta:
        description = "Heuristic detection of suspicious LabVIEW VI files that may target CVE-2026-16233 memory corruption"
        author = "valtersit.com"
        date = "2026-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-16233"
        cve = "CVE-2026-16233"

    strings:
        $vi_magic = { 4C 56 39 39 }              // heuristic marker used in VI-like artifacts (illustrative)
        $lv_hdr1  = "LVSR" ascii
        $lv_hdr2  = "LabVIEW" ascii nocase
        $lv_hdr3  = "RSRC" ascii
        $html     = "<html" ascii nocase
        $url      = "http" ascii nocase

    condition:
        (uint32(0) == 0x53524256 or $lv_hdr1) and
        ($lv_hdr2 or $lv_hdr3) and
        not $html and
        filesize < 5MB
}

Suricata IDS Rule

alert smb any any -> any any (msg:"CVE-2026-16233 Possible LabVIEW VI File Transfer (SMB)"; flow:to_server,established; content:"|FF|SMB"; depth:4; content:".vi"; nocase; offset:100; depth:64; classtype:attempted-user; sid:202616233; rev:1; metadata:cve CVE-2026-16233, created_at 2026_01_01, updated_at 2026_01_01; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-16233;)

Elastic Detection

process where process.name : ("LabVIEW.exe", "LabVIEWCLI.exe") and
process.args : ("*\\Downloads\\*", "*\\Temp\\*", "*\\AppData\\Local\\Temp\\*", "*\\Users\\Public\\*")

Splunk SPL Query

index=endpoint_sysmon source="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" EventCode=1
| eval proc=lower(Image)
| where (like(proc, "%labview%") OR like(proc, "%labviewcli%"))
| where (like(CommandLine, "%\\Downloads\\%") OR like(CommandLine, "%\\Temp\\%") OR like(CommandLine, "%\\AppData\\Local\\Temp\\%") OR like(CommandLine, "%\\Users\\Public\\%"))
| stats count min(_time) as first_seen max(_time) as last_seen values(CommandLine) as cmd by ComputerName, User, Image
| sort - first_seen

Wazuh OSSEC Rule

<group name="windows,sysmon,cve-2026-16233,">
  <rule id="202616233" level="10">
    <if_sid>61603</if_sid>
    <field name="win.eventdata.image">(?i)labview(cli)?\.exe$</field>
    <field name="win.eventdata.commandLine">(?i)(\\Downloads\\|\\Temp\\|\\AppData\\Local\\Temp\\|\\Users\\Public\\)</field>
    <description>CVE-2026-16233: LabVIEW launched on file from untrusted/download path - possible crafted VI exploitation</description>
    <mitre>
      <id>T1204.002</id>
    </mitre>
    <group>cve_2026_16233,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence is 2/4 (CLAIMED — a single source, NVD, claims a patch exists, but this is not independently confirmed, and no vendor fix version or advisory text was supplied in the intelligence data). Treat patch status as unverified.

1) Immediate mitigations (while patch status is unconfirmed):

• Treat all VI files from external or untrusted sources as suspicious. Block VI attachments at the email gateway and quarantine VI files arriving via web downloads or shared file services from outside the trusted engineering network.
• Apply Mark-of-the-Web / attachment restrictions so files from external origins cannot execute silently by policy.
• Restrict interactive access to LabVIEW engineering workstations; enforce least privilege so a compromised LabVIEW process does not run with administrative rights.
• Monitor EDR/Sysmon for LabVIEW processes opening VI files from Downloads, Temp, AppData, or Public directories (see detection rules above).
• If LabVIEW is not required on a host, uninstall or isolate it; if an internet-facing or shared deployment exists, limit who and what can deliver files to it.

2) Patch/upgrade steps (once a vendor fix is confirmed):

• Monitor NI's official security advisory channel for CVE-2026-16233 and the confirmed fixed LabVIEW version.
• Upgrade LabVIEW from 2026 Q3 (26.3.0) and prior to the first version NI identifies as fixed. Do not deploy an unverified third-party "patch."
• After upgrading, re-scan engineering workstations and validate that the fixed build is in place across all installations, including air-gapped systems fed by update media.
• Because patch confidence is only 2/4, do not rely solely on the claimed fix — maintain the interim mitigations until the vendor advisory is published and independently corroborated.

3) Long-term hardening:

• Establish a signed, curated internal library of approved VI files; require cryptographic verification of project artifacts before they are opened.
• Segment engineering workstations from IT and OT networks to limit lateral movement if code execution occurs.
• Apply exploit mitigations where available (ASLR, DEP, CFG) and keep the OS and LabVIEW runtime fully patched.
• Integrate VI-file scanning (YARA) into file-ingress pipelines and routinely audit for unusual LabVIEW file activity.
• Train engineers to recognize phishing and supply-chain attempts delivering project files.

References

1. NVD — CVE-2026-16233: https://nvd.nist.gov/vuln/detail/CVE-2026-16233
2. MITRE CWE-787 — Out-of-bounds Write: https://cwe.mitre.org/data/definitions/787.html
3. FIRST — CVSS 3.1 Specification: https://www.first.org/cvss/specification-document
4. NI Product Security / Security Advisories (vendor channel — verify current advisory for CVE-2026-16233 before relying on patch claims): https://www.ni.com/en-us/support/documentation/security-advisories.html
5. CISA Known Exploited Vulnerabilities Catalog (verify inclusion; CVE-2026-16233 was NOT listed at time of analysis): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No confirmed threat actor campaign or exploit-in-the-wild evidence was provided for CVE-2026-16233. EPSS 0.00128 (2.0% percentile) indicates low predicted mass-exploitation activity, and the CVE is not in CISA KEV; a public PoC reference is noted but no exploit code was supplied, and the attack chain described above is inferred from the vulnerability class and the NVD-stated trigger condition.