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Weakness · BaseCWE-256

CWE-256: Plaintext Storage of a Password

Likelihood of exploit: HighBase

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.

CVEs
4Mapped to CWE-256
CISA KEV
0None listed yet
Critical
1CVSS v3 critical CVEs
Threats
16Tracked campaigns citing it
Likelihood
HighMITRE likelihood of exploit

Last updated:

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 (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.

Affected vendors

Threat activity

16 tracked threats cite CWE-256:

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.