CVE-2026-18445

Executive Summary

CVE-2026-18445 is an integer overflow leading to an out-of-bounds write in NI LabVIEW, affecting LabVIEW 2026 Q3 and all prior versions. An attacker must convince a target user to open a specially crafted VI (Virtual Instrument) file; successful exploitation can result in information disclosure or arbitrary code execution on the victim host. The vulnerability is local in attack vector with a required user interaction (CVSS 6.6), and no public proof-of-concept, Nuclei template, or KEV listing currently exists, indicating a low observed exploitation footprint at time of writing.

Technical Analysis

NI LabVIEW is a graphical development environment that stores programs as VI files — a proprietary binary container holding a block diagram, front panel definition, and compiled/data-segment metadata. The vulnerability class is CWE-190 (Integer Overflow or Wraparound) that manifests as an out-of-bounds write (memory corruption) during VI file processing.

The mechanism, as stated by NVD, is an integer overflow that leads to a write outside an allocated memory region. In binary-parser contexts, this typically arises when a length, count, or offset field parsed from the file is used in an arithmetic operation (e.g., a size calculation for a buffer allocation) without adequate bounds validation. When the value wraps around an integer boundary, the resulting computed size or index becomes smaller or larger than expected, and subsequent writes land outside the intended buffer. Because VI files are parsed by the LabVIEW runtime/editor on open, a malformed field inside the file is sufficient to reach the vulnerable code path.

The attack surface is the VI file parser. Exploitation requires the user to open a malicious file, placing this squarely at the application/file-parser boundary rather than a network service. Per CVSS, Access Vector is Local, Attack Complexity is Low, Privileges Required is None, and User Interaction is Required. The scope is Unchanged. The impact vector is Confidentiality:Low, Integrity:Low, Availability:High — consistent with a memory-corruption primitive that may leak memory (info disclosure) or hand control flow to attacker data (arbitrary code execution), while the out-of-bounds write reliably risks a crash (availability).

Important accuracy note: The NVD description does not disclose the specific function, structure, or file-offset involved. No function names, API paths, or field identifiers can be asserted. All statements above remain at the vulnerability-class and parser-boundary level, derived strictly from the CVE description.

Exploitation Scenarios

No public PoC is available; the attack chain below is inferred from the vulnerability class (integer overflow → out-of-bounds write) and the stated exploitation precondition ("user to open a specially crafted VI file").

1. Reconnaissance / target identification. The attacker identifies environments using NI LabVIEW, typically engineering, test-and-measurement, automated validation, and industrial control labs. Targets are users who routinely receive and open VI files from colleagues, vendors, or shared project repositories. No network exposure is required, so discovery focuses on people and file-exchange workflows rather than internet-facing hosts.

2. Triggering the flaw class. The attacker crafts a VI file whose encoded length/count/offset field is set to a value that overflows during the runtime's internal size or index computation. When the victim opens the VI, LabVIEW parses the crafted field, the arithmetic wraps, and the out-of-bounds write occurs. Delivering the file requires only that the user double-click or otherwise open it within the LabVIEW environment — consistent with T1204.002 (User Execution: Malicious File). Common delivery vectors are email attachments, shared network drives, chat/file-transfer applications, or a compromised project repository.

3. Payload / execution method (class level). The out-of-bounds write gives the attacker a memory-corruption primitive. Depending on the crafted values, this can be steered toward (a) leaking adjacent memory to disclose sensitive content, or (b) corrupting control-adjacent data to redirect execution to attacker-controlled content — the arbitrary-code-execution outcome described by NVD. Journalists/analysts must treat the specific primitive (heap vs. stack, exact corruption target) as unknown, since NVD does not specify it and no PoC exists to confirm.

4. Post-exploitation impact. Because exploitation occurs in the context of the user running LabVIEW, code execution (if achieved) would run with that user's privileges on the workstation, enabling data access, lateral movement from the engineering host, or tampering with test/measurement results. Absent successful code execution, the most likely observable outcome is a crash of the LabVIEW process due to the out-of-bounds write.

Impact Assessment

CVSS 3.1 base score 6.6 (Medium). Subscores: AV:L (the file must be opened locally, not exploited remotely over a socket), AC:L (no special conditions beyond opening the file), PR:N (no authentication needed), UI:R (victim must open the malicious VI), S:U (impact confined to the vulnerable component), C:L / I:L / A:H. The High Availability impact reflects the strong likelihood of a process crash from a corrupted write; the Low Confidentiality/Integrity impacts reflect that disclosure or modification is possible but not guaranteed by a single primitive.

Blast radius is per-workstation and centered on engineering/test environments. Where LabVIEW is used to drive hardware, instrumentation, or validation pipelines, a crash or code execution on the operator host can disrupt test campaigns and potentially influence the integrity of recorded measurements. Because delivery is file-based and targets a trusted engineering workflow, a single compromised shared repository or supplier can seed many workstations. There is currently no evidence of active exploitation (EPSS 0.00133, 2.3rd percentile; not listed in CISA KEV), so the primary risk today is targeted, social-engineering-driven delivery rather than opportunistic mass exploitation.

Detection Guidance

Sigma Rule

Detects LabVIEW process spawning from an unexpected parent or an unsigned/crafted VI causing a crash, approximating the open-of-malicious-file behavior.

title: Suspicious LabVIEW VI File Open Leading to Crash or Child Process
id: 8f2a1c6e-3b7d-4e91-9d2a-labviewintoverflow01
status: experimental
description: Detects LabVIEW opening files from user-writable or download directories and/or crashing, consistent with CVE-2026-18445 malicious VI file processing.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-18445
author: valtersit.com
date: 2026/01/01
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    Image|endswith:
      - '\LabVIEW.exe'
      - '\LabVIEWCE.exe'
  selection_path:
    CommandLine|contains:
      - '\Downloads\'
      - '\AppData\Local\Temp\'
      - '\Desktop\'
      - '\Users\Public\'
  condition: selection_img and selection_path
fields:
  - Image
  - CommandLine
  - ParentImage
  - User
falsepositives:
  - Legitimate developers opening project files from local working directories
level: medium
tags:
  - attack.t1204.002
  - cve.2026.18445

YARA Rule

Detects VI files containing oversized/overflowing length-indicator patterns. Because no PoC specifies byte offsets, this rule targets VI file structure heuristically and should be tuned against known-good VI samples before production use.

rule CVE_2026_18445_LabVIEW_VI_Integer_Overflow
{
    meta:
        description = "Heuristic detection of LabVIEW VI files with suspicious length/size fields consistent with CVE-2026-18445 integer overflow"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-18445"
        date = "2026-01-01"
        severity = "medium"

    strings:
        $vi_sig = { 4C 56 39 39 }        // "LV99" VI file signature
        $vi_hdr = "RSRC"                  // common VI resource block marker
        $big1 = { FF FF FF 7F }           // INT32_MAX sentinel often used in overflow abuse
        $big2 = { 00 00 00 80 }           // INT32_MIN sentinel

    condition:
        $vi_sig at 0 and
        filesize < 20MB and
        (uint32(0) == 0x39395 4C56 or $vi_sig) and
        any of ($big1, $big2)
}

Note: The signature/length tokens above are heuristic markers for VI-format analysis, not values confirmed from the CVE. Validate and adjust offsets against your LabVIEW version's VI format before deployment.

Suricata IDS Rule

Detects VI files transferred over common file-exfil/delivery channels (HTTP and SMB) so that malicious VIs can be flagged in transit.

alert http any any -> any any (msg:"CVE-2026-18445 Possible LabVIEW VI File Transfer (Malicious VI Delivery)"; flow:established,to_client; http.response_body; content:"LV99"; depth:4; fileext:"vi"; filestore; sid:2026184451; rev:1; metadata:created_at 2026_01_01, cve CVE_2026_18445; classtype:attempted-user;)
alert smb any any -> any any (msg:"CVE-2026-18445 LabVIEW VI File Over SMB"; flow:established,to_client; content:"|FF|SMB"; dsize:>0; fileext:"vi"; filestore; sid:2026184452; rev:1; metadata:created_at 2026_01_01, cve CVE_2026_18445; classtype:attempted-user;)

Elastic Detection

Detects the LabVIEW process opening files from untrusted directories and generating crash events, correlated to the user-execution trigger.

sequence by host.id, user.id with maxspan=5s
  [ process where process.name : "LabVIEW.exe" and
      process.args : ("*\\Downloads\\*", "*\\AppData\\Local\\Temp\\*", "*\\Users\\Public\\*") ]
  [ file where event.action == "modification" and
      file.path : ("*\\Temp\\*.vi", "*\\Downloads\\*.vi") ]

Splunk SPL Query

Correlates LabVIEW process creation with file-open activity and application crashes for CVE-2026-18445 triage.

index=endpoint (Image="*\\LabVIEW.exe" OR Image="*\\LabVIEWCE.exe")
| join type=left host [
    search index=endpoint EventCode=1000 (Message="*LabVIEW*" OR Application="*LabVIEW*")
    | rename host as host, Message as CrashMessage ]
| eval suspicious_path=if(match(CommandLine, "(?i)(\\\\Downloads\\\\|\\\\AppData\\\\Local\\\\Temp\\\\|\\\\Users\\\\Public\\\\)"), "yes", "no")
| where suspicious_path="yes" OR isnotnull(CrashMessage)
| table _time host User Image CommandLine ParentImage suspicious_path CrashMessage
| sort - _time

Wazuh OSSEC Rule

Monitors for LabVIEW process execution from user-writable paths and application fault events on Windows agents.

<group name="windows,labview,cve_2026_18445,">
  <rule id="100845" level="10">
    <if_sid>61603</if_sid>
    <field name="win.eventdata.image">LabVIEW\.exe$</field>
    <field name="win.eventdata.commandLine">(?i)(Downloads|AppData\\Local\\Temp|Users\\Public).*\.vi</field>
    <description>CVE-2026-18445: LabVIEW opened a VI file from a suspicious user-writable path - possible malicious VI processing.</description>
    <mitre>
      <id>T1204.002</id>
    </mitre>
  </rule>

  <rule id="100846" level="12">
    <if_sid>60009</if_sid>
    <field name="win.system.providerName">Application Error</field>
    <match>LabVIEW</match>
    <description>CVE-2026-18445: LabVIEW application fault detected - possible out-of-bounds write crash from crafted VI file.</description>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 2/4 (CLAIMED — a single source, NVD, states a fix exists; there is no independently confirmed vendor advisory, fix version, or reference in the provided data). Treat the environment as unpatched until NI publishes and you verify an official advisory.

1. Immediate mitigations:

• Restrict opening of VI files to trusted, verified sources; block VI files at email gateways and web/SMB file-transfer inspection pending verification.
• Where feasible, open untrusted or third-party VI files in an isolated sandbox or dedicated low-privilege VM without access to production networks or instrumentation.
• Enable application crash telemetry on LabVIEW workstations and monitor for repeated faults tied to file opens (see detection rules above).
• Limit the privileges of LabVIEW operator accounts to reduce post-exploitation reach if code execution succeeds.

2. Patch / upgrade steps:

• Monitor NI's official security advisory channels for a LabVIEW release addressing CVE-2026-18445, and confirm the fixed version directly with NI before relying on any claim.
• Once a vendor-confirmed fixed release is available, test in a lab and stage upgrades across LabVIEW 2026 Q3 and prior installations, prioritizing hosts in regulated or production test pipelines.
• Track the CVE record (NVD) for updated references, corrected version ranges, and any added vendor advisory links.

3. Long-term hardening:

• Establish a software-component and firmware inventory that captures LabVIEW versions across engineering teams to speed future vulnerability response.
• Apply file-origin controls and allow-listing for engineering repositories; verify integrity/provenance of shared VI files.
• Adopt defense-in-depth for engineering workstations (least privilege, application control, endpoint detection and response with memory-corruption and crash monitoring) since file-parser memory-corruption bugs recur across development tooling.

References

1. NVD — CVE-2026-18445: https://nvd.nist.gov/vuln/detail/CVE-2026-18445
2. CWE-190 — Integer Overflow or Wraparound: https://cwe.mitre.org/data/definitions/190.html
3. MITRE ATT&CK T1204.002 — User Execution: Malicious File: https://attack.mitre.org/techniques/T1204/002/
4. NI (National Instruments) security advisories portal (monitor for a CVE-2026-18445 advisory and fixed version): https://www.ni.com/en/support/security.html
5. CISA Known Exploited Vulnerabilities catalog (verify status; CVE-2026-18445 not currently listed): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Threat actor / exploitation evidence: None reported. EPSS 0.00133 (2.3rd percentile), no CISA KEV listing, no public PoC, and no Nuclei template or exploit code available as of this report. No known campaigns are associated with this CVE in the provided data.