# CWE-256: Plaintext Storage of a Password **Likelihood of exploit:** High > As of 2026-11-07, CWE-256 (Plaintext Storage of a Password) underlies 4 CVEs tracked by Threadlinqs, none of them in the CISA Known Exploited Vulnerabilities catalog, and is cited by 16 tracked threats. MITRE rates its likelihood of exploit as High. **Last updated:** 2026-11-07 ## What is CWE-256? The product stores a password in plaintext within resources such as memory or files. CWE-256 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; Technology: ICS/OT. _Source: [MITRE CWE](https://cwe.mitre.org/data/definitions/256.html) (CWE-256 definition, reproduced verbatim). Counts and linkage below are Threadlinqs data._ ## Consequences - **Access Control** — Gain Privileges or Assume Identity. Storing a plaintext password in a configuration file allows anyone who can read the file to access the password-protected resource. In some contexts, even storage of a plaintext password in memory is considered a security risk if the password is not cleared immediately after it is used. _Source: MITRE CWE, common consequences._ ## How CWE-256 is exploited in the wild Threadlinqs maps 4 CVEs to CWE-256, published between 2026-02-27 and 2026-10-15. None of them is in the CISA KEV catalog yet. By CVSS v3 severity the set splits into 1 critical, 1 high. The highest EPSS score in the set is 0.2% (CVE-2026-63315), the modelled probability of exploitation in the next 30 days. 16 tracked threats reference CWE-256 directly or through a CVE it covers; the most recent is “BlackNevas and The Gentlemen Ransomware Cases Against ESXi and Proxmox Virtualization Environments” (2026-11-06). Affected products concentrate in Johnson Controls (1), Pronetiqs (1), Slican (1), among 4 vendors in total. ## Vulnerabilities (CVEs) All 4 CVEs mapped to CWE-256, CISA KEV first, then by CVSS score. - [CVE-2026-21660](https://intel.threadlinqs.com/cve/CVE-2026-21660) — CVSS 9.8 critical · EPSS 0.2% · published 2026-02-27 - [CVE-2026-40430](https://intel.threadlinqs.com/cve/CVE-2026-40430) — CVSS 7.5 high · EPSS 0.2% · published 2026-07-23 - [CVE-2026-63315](https://intel.threadlinqs.com/cve/CVE-2026-63315) — EPSS 0.2% · published 2026-10-15 - [CVE-2026-50641](https://intel.threadlinqs.com/cve/CVE-2026-50641) — EPSS 0.2% · published 2026-07-29 ## Affected vendors - [Johnson Controls](https://intel.threadlinqs.com/vendors/johnson-controls) — 1 CVE - [Pronetiqs](https://intel.threadlinqs.com/vendors/pronetiqs) — 1 CVE - **Slican** — 1 CVE - **Streamsoft** — 1 CVE ## Threat activity 16 tracked threats cite CWE-256: - [BlackNevas and The Gentlemen Ransomware Cases Against ESXi and Proxmox Virtualization Environments](https://intel.threadlinqs.com/threat/TL-2026-5405) — HIGH · 2026-11-06 - [CVE-2026-21660: Hardcoded Credentials in Johnson Controls Frick Controls Quantum HD Industrial Refrigeration Controller](https://intel.threadlinqs.com/threat/TL-2026-4350) — MEDIUM · 2026-10-24 - [Navigate360 / P3 Global Intel breach by Internet Yiff Machine exposes anonymous Crime Stoppers tips; Toronto Crime Stoppers suspends operations](https://intel.threadlinqs.com/threat/TL-2026-4183) — HIGH · 2026-10-22 - [Developer credential exposure on dev machines: StepSecurity Dev Machine Guard credential-source inventory (context: TeamPCP stealer, Bitwarden CLI npm hijack, Shai-Hulud)](https://intel.threadlinqs.com/threat/TL-2026-4004) — MEDIUM · 2026-10-21 - [Slican Telephone Exchanges: Hardcoded Encryption Key (CVE-2026-35088) and WebCTI SQL Injection / Plaintext Password Storage (CVE-2026-63314, CVE-2026-63315)](https://intel.threadlinqs.com/threat/TL-2026-3700) — HIGH · 2026-10-16 - [CVE-2026-21660: Hardcoded Credentials in Johnson Controls Frick Controls Quantum HD Industrial Refrigeration Controller](https://intel.threadlinqs.com/threat/TL-2026-3571) — MEDIUM · 2026-10-15 - [CVE-2026-50641: Plaintext Password Storage in Streamsoft Business Intelligence](https://intel.threadlinqs.com/threat/TL-2026-1825) — HIGH · 2026-08-03 - [Krybit Ransomware — Babuk-Derived RaaS Operation Emerges with Double Extortion](https://intel.threadlinqs.com/threat/TL-2026-1263) — HIGH · 2026-07-13 - [Dark Web Identity-Theft Ecosystem: $0.95 Fullz, STORM Infostealer-as-a-Service, and Scam-as-a-Service Marketplaces](https://intel.threadlinqs.com/threat/TL-2026-0919) — HIGH · 2026-06-23 - [FortiBleed: Russian-Speaking Credential-Harvesting Campaign Against Internet-Exposed FortiGate Firewalls and SSL VPN Gateways](https://intel.threadlinqs.com/threat/TL-2026-0895) — CRITICAL · 2026-06-21 - [UNC6508 (PRC-Nexus) Trojanizes Unpatched REDCap Research Servers with INFINITERED Malware to Spy on North American Medical, Academic & Military Research](https://intel.threadlinqs.com/threat/TL-2026-0891) — HIGH · 2026-06-20 - [FortiBleed Campaign: Mass FortiGate SSL VPN / Admin Credential Exposure Affecting ~73,932 Fortinet Firewalls Across 194 Countries](https://intel.threadlinqs.com/threat/TL-2026-0868) — CRITICAL · 2026-06-13 - [DarkCloud Infostealer — Commercial VB6 Credential-Harvesting Malware (A310Logger/BluStealer Successor)](https://intel.threadlinqs.com/threat/TL-2026-0765) — HIGH · 2026-06-10 - [Grafana Labs Source Code Theft via Stolen GitHub Access Token — CoinbaseCartel Extortion Campaign](https://intel.threadlinqs.com/threat/TL-2026-0527) — HIGH · 2026-05-18 - [Amazon SES Weaponized for Phishing & BEC via Leaked AWS IAM Access Keys (Securelist, May 2026)](https://intel.threadlinqs.com/threat/TL-2026-0451) — HIGH · 2026-05-04 - [UNC4899/Jade Sleet Cryptocurrency Exchange Breach via AirDrop Trojanization and Cloud Infrastructure Compromise](https://intel.threadlinqs.com/threat/TL-2026-0202) — CRITICAL · 2026-03-09 ## Mitigations - **Architecture and Design**: Avoid storing passwords in easily accessible locations. - **Architecture and Design**: Consider storing cryptographic hashes of passwords as an alternative to storing in plaintext. - **General**: A programmer might attempt to remedy the password management problem by obscuring the password with an encoding function, such as base 64 encoding, but this effort does not adequately protect the password because the encoding can be detected and decoded easily. _Source: MITRE CWE, potential mitigations._ ## Detection methods (MITRE CWE) - **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.) _Source: MITRE CWE, detection methods. Threadlinqs detection rules for the threats above are Blue tier and higher._ ## Related weaknesses - [CWE-522 Insufficiently Protected Credentials](https://intel.threadlinqs.com/cwe/CWE-522) Canonical: https://intel.threadlinqs.com/cwe/CWE-256 Source definition: https://cwe.mitre.org/data/definitions/256.html Detection rules and IOCs for threats exploiting CWE-256 unlock per threat with TL Creds (https://threadlinqs.com/tl-creds); the Threadlinqs MCP server (Purple) serves them to AI agents: https://intel.threadlinqs.com/mcp