# CWE-426: Untrusted Search Path

**Likelihood of exploit:** High · **KEV-linked**

> As of 2026-10-14, CWE-426 (Untrusted Search Path) underlies 3 CVEs tracked by Threadlinqs, 1 of them in the CISA Known Exploited Vulnerabilities catalog, and is cited by 42 tracked threats. MITRE rates its likelihood of exploit as High.

**Last updated:** 2026-10-14

## What is CWE-426?

The product searches for critical resources using an externally-supplied search path that can point to resources that are not under the product's direct control.

This might allow attackers to execute their own programs, access unauthorized data files, or modify configuration in unexpected ways. If the product uses a search path to locate critical resources such as programs, then an attacker could modify that search path to point to a malicious program, which the targeted product would then execute. The problem extends to any type of critical resource that the product trusts. Some of the most common variants of untrusted search path are: In various UNIX and Linux-based systems, the PATH environment variable may be consulted to locate executable programs, and LD_PRELOAD may be used to locate a separate library. In various Microsoft-based systems, the PATH environment variable is consulted to locate a DLL, if the DLL is not found in other paths that appear earlier in the search order.

CWE-426 is a base-level weakness in MITRE’s Common Weakness Enumeration, with a MITRE likelihood of exploit of High. Applicable platforms: Language: Not Language-Specific; Operating_System: Not OS-Specific.

_Source: [MITRE CWE](https://cwe.mitre.org/data/definitions/426.html) (CWE-426 definition, reproduced verbatim). Counts and linkage below are Threadlinqs data._

## Consequences

- **Integrity, Confidentiality, Availability, Access Control** — Gain Privileges or Assume Identity, Execute Unauthorized Code or Commands. There is the potential for arbitrary code execution with privileges of the vulnerable program.
- **Availability** — DoS: Crash, Exit, or Restart. The program could be redirected to the wrong files, potentially triggering a crash or hang when the targeted file is too large or does not have the expected format.
- **Confidentiality** — Read Files or Directories. The program could send the output of unauthorized files to the attacker.

_Source: MITRE CWE, common consequences._

## How CWE-426 is exploited in the wild

Threadlinqs maps 3 CVEs to CWE-426, published between 2012-07-10 and 2026-10-12. 1 is listed in CISA’s Known Exploited Vulnerabilities catalog, the authoritative record of exploitation in the wild. By CVSS v3 severity the set splits into 3 high. The highest EPSS score in the set is 21.0% (CVE-2012-1854), the modelled probability of exploitation in the next 30 days. 42 tracked threats reference CWE-426 directly or through a CVE it covers; the most recent is “October 2026 Microsoft Patch Tuesday: Exploited Windows Shell MotW Bypass (CVE-2026-96951), 1,417 Vulnerabilities Patched” (2026-10-13). Affected products concentrate in Adobe (1), IBM (1).

## Vulnerabilities (CVEs)

All 3 CVEs mapped to CWE-426, CISA KEV first, then by CVSS score.

- [CVE-2012-1854](https://intel.threadlinqs.com/cve/CVE-2012-1854) — CISA KEV · CVSS 7.8 high · EPSS 21.0% · published 2012-07-10
- [CVE-2026-75768](https://intel.threadlinqs.com/cve/CVE-2026-75768) — CVSS 7.8 high · EPSS 0.2% · published 2026-08-25
- [CVE-2026-75782](https://intel.threadlinqs.com/cve/CVE-2026-75782) — CVSS 7.8 high · published 2026-10-12

## Affected vendors

- [Adobe](https://intel.threadlinqs.com/vendors/adobe) — 1 CVE
- [IBM](https://intel.threadlinqs.com/vendors/ibm) — 1 CVE

## Threat activity

42 tracked threats cite CWE-426; the 25 most recent are listed.

- [October 2026 Microsoft Patch Tuesday: Exploited Windows Shell MotW Bypass (CVE-2026-96951), 1,417 Vulnerabilities Patched](https://intel.threadlinqs.com/threat/TL-2026-3443) — CRITICAL · 2026-10-13
- [Adobe and Nvidia Patch Dozens of Vulnerabilities Across Multiple Products, Including Two Critical Flaws in Nvidia's NemoClaw AI Agent Stack and a CVSS 10.0 Adobe Campaign Classic Chain](https://intel.threadlinqs.com/threat/TL-2026-2152) — CRITICAL · 2026-08-26
- [91 Spring Framework CVEs Disclosed by Broadcom, Including Critical Deserialization Flaw CVE-2026-59285](https://intel.threadlinqs.com/threat/TL-2026-2105) — CRITICAL · 2026-08-21
- [Unpatched Cursor IDE 0-Day: Malicious git.exe in Repository Root Enables Arbitrary Code Execution on Windows (CWE-427)](https://intel.threadlinqs.com/threat/TL-2026-1377) — HIGH · 2026-07-15
- [TONResolver Remote Access Trojan - Active Campaign Targeting Japanese Hospitality Sector](https://intel.threadlinqs.com/threat/TL-2026-1010) — HIGH · 2026-06-30
- [Synology MailPlus Server Critical Remote Code Execution and Arbitrary File Access (CVE-2026-13136, CVE-2025-15660, CVE-2026-13135)](https://intel.threadlinqs.com/threat/TL-2026-1014) — CRITICAL · 2026-06-30
- [Mistic Windows Backdoor - In-Memory Code Execution via DLL Sideloading](https://intel.threadlinqs.com/threat/TL-2026-1017) — CRITICAL · 2026-06-30
- [ClickFix Campaign Deploying Potemkin Loader, RMMProject RAT, and EtherRAT - May 2026 Enterprise Compromise](https://intel.threadlinqs.com/threat/TL-2026-0972) — CRITICAL · 2026-06-28
- [JadeSnow: Hijacked npm/Go Supply Chain Attack with VSCode Exploitation and Blockchain Dead Drops](https://intel.threadlinqs.com/threat/TL-2026-0987) — CRITICAL · 2026-06-28
- [Dropping Elephant Malware Campaign - China-Themed Loader Chain for Initial Access and Payload Delivery](https://intel.threadlinqs.com/threat/TL-2026-0989) — CRITICAL · 2026-06-28
- [Cloud vn105rkj64 — Italian Invoice Phishing Drops Windows Backdoor and Force-Installed Chrome Extension Abusing Native Messaging for Cookie Theft, MFA Bypass, and Remote PowerShell](https://intel.threadlinqs.com/threat/TL-2026-0948) — HIGH · 2026-06-26
- [Versatile Werewolf (HeartlessSoul): Fondue.exe LOLBin Abuse via APPWIZ.cpl Side-Loading Delivers Sliver Implant and SoullessRAT](https://intel.threadlinqs.com/threat/TL-2026-0861) — HIGH · 2026-06-18
- [OnionDrop Loader Campaign Delivers LegionLoader/CurlyGate, CGrabber, and Vidar via DLL Sideloading and gainmsg\[.\]com C2](https://intel.threadlinqs.com/threat/TL-2026-0831) — HIGH · 2026-06-17
- [OceanLotus (APT32) Supply-Chain Compromise of FireAnt MetaKit Delivers SPECTRALVIPER Backdoor to Vietnamese Stock Investors](https://intel.threadlinqs.com/threat/TL-2026-0795) — HIGH · 2026-06-14
- [Atomic Arch: AUR Package Supply Chain Compromise Using Malicious npm Packages](https://intel.threadlinqs.com/threat/TL-2026-0979) — CRITICAL · 2026-06-12
- [Iranian "Dream Job" Campaign (TA455 / Charming Kitten) — SnailResin Loader & SlugResin Backdoor Targeting Aerospace, Aviation & Defense](https://intel.threadlinqs.com/threat/TL-2026-0763) — HIGH · 2026-06-10
- [DBatLoader (ModiLoader/NatsoLoader): Delphi-Compiled Windows Loader Using Layered Anti-Analysis, Mock-Trusted-Directory UAC Bypass, and DLL Side-Loading to Deliver Remcos, FormBook, NetWire and Warzone](https://intel.threadlinqs.com/threat/TL-2026-0768) — HIGH · 2026-06-10
- [RenEngine Loader — Pirated Game Installers Abuse Ren'Py Python Launchers + DLL Side-Loading to Deliver HijackLoader and Lumma/ACR/Vidar Stealers](https://intel.threadlinqs.com/threat/TL-2026-0716) — HIGH · 2026-06-08
- [Nimbus Manticore (UNC1549 / Smoke Sandstorm) Fake Ebix Recruitment Portal — TOTPGuard.dll AppDomainManager Hijacking Sideloading Chain Delivering main.dll Implant](https://intel.threadlinqs.com/threat/TL-2026-0656) — HIGH · 2026-06-02
- [Mustang Panda PlugX RAT — Multi-Stage Fake Browser Update Chain via G DATA AntiVirus DLL Sideloading (BlueCyber)](https://intel.threadlinqs.com/threat/TL-2026-0658) — HIGH · 2026-06-02
- [Notepad++ v8.9.6 — Critical Arbitrary Code Execution via config.xml commandLineInterpreter and shortcuts.xml (CVE-2026-48770, CVE-2026-48778, CVE-2026-48800)](https://intel.threadlinqs.com/threat/TL-2026-0613) — CRITICAL · 2026-05-28
- [GPU-Targeted Cryptojacking Campaign — SEO + AI Chatbot Poisoning Delivers ScreenConnect & SimpleRunPE Process Hollowing into .NET Utilities (Microsoft Defender Experts)](https://intel.threadlinqs.com/threat/TL-2026-0597) — HIGH · 2026-05-26
- [Lazarus RemotePE Memory-Only RAT — DPAPILoader + RemotePELoader Chain Targeting Financial & Cryptocurrency Firms](https://intel.threadlinqs.com/threat/TL-2026-0579) — HIGH · 2026-05-25
- [Nimbus Manticore (UNC1549/IRGC) SQL Developer SEO Poisoning Campaign Delivers MiniFast Backdoor via AppDomain Hijacking — Operation Epic Fury Wave 3](https://intel.threadlinqs.com/threat/TL-2026-0581) — HIGH · 2026-05-25
- [bandcampro — Solo Russian-Speaking Actor Operating Persistent Gemini CLI Jailbreak (GEMINI.md), AI-Assisted WordPress Credential Cracking, MAGA/QAnon Influence Operation & StellarMonSetup.exe GoToResolve Crypto Drainer (TrendAI Research, May 2026)](https://intel.threadlinqs.com/threat/TL-2026-0582) — HIGH · 2026-05-25

## Mitigations

- **Architecture and Design, Implementation / Attack Surface Reduction**: Hard-code the search path to a set of known-safe values (such as system directories), or only allow them to be specified by the administrator in a configuration file. Do not allow these settings to be modified by an external party. Be careful to avoid related weaknesses such as CWE-426 and CWE-428.
- **Implementation**: When invoking other programs, specify those programs using fully-qualified pathnames. While this is an effective approach, code that uses fully-qualified pathnames might not be portable to other systems that do not use the same pathnames. The portability can be improved by locating the full-qualified paths in a centralized, easily-modifiable location within the source code, and having the code refer to these paths.
- **Implementation**: Remove or restrict all environment settings before invoking other programs. This includes the PATH environment variable, LD_LIBRARY_PATH, and other settings that identify the location of code libraries, and any application-specific search paths.
- **Implementation**: Check your search path before use and remove any elements that are likely to be unsafe, such as the current working directory or a temporary files directory.
- **Implementation**: Use other functions that require explicit paths. Making use of any of the other readily available functions that require explicit paths is a safe way to avoid this problem. For example, system() in C does not require a full path since the shell can take care of it, while execl() and execv() require a full path.

_Source: MITRE CWE, potential mitigations._

## Detection methods (MITRE CWE)

- **Black Box**: Use monitoring tools that examine the software's process as it interacts with the operating system and the network. This technique is useful in cases when source code is unavailable, if the software was not developed by you, or if you want to verify that the build phase did not introduce any new weaknesses. Examples include debuggers that directly attach to the running process; system-call tracing utilities such as truss (Solaris) and strace (Linux); system activity monitors such as FileMon…
- **Automated Static Analysis** (effectiveness: High): Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
- **Manual Analysis**: Use tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

_Source: MITRE CWE, detection methods. Threadlinqs detection rules for the threats above are Blue tier and higher._

## Related weaknesses

- [CWE-642](https://cwe.mitre.org/data/definitions/642.html)
- [CWE-668 Exposure of Resource to Wrong Sphere](https://intel.threadlinqs.com/cwe/CWE-668)
- [CWE-673](https://cwe.mitre.org/data/definitions/673.html)
- [CWE-427 Uncontrolled Search Path Element](https://intel.threadlinqs.com/cwe/CWE-427)
- [CWE-428](https://cwe.mitre.org/data/definitions/428.html)

Canonical: https://intel.threadlinqs.com/cwe/CWE-426
Source definition: https://cwe.mitre.org/data/definitions/426.html
Detection rules and IOCs for threats exploiting CWE-426 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp