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Weakness · VariantCWE-259

CWE-259: Use of Hard-coded Password

Likelihood of exploit: HighKEV-linkedVariant

As of 2026-10-10, CWE-259 (Use of Hard-coded Password) underlies 3 CVEs tracked by Threadlinqs, 1 of them in the CISA Known Exploited Vulnerabilities catalog, and is cited by 3 tracked threats. MITRE rates its likelihood of exploit as High.

CVEs
3Mapped to CWE-259
CISA KEV
1Exploited in the wild
Critical
1CVSS v3 critical CVEs
Threats
3Tracked campaigns citing it
Likelihood
HighMITRE likelihood of exploit

Last updated:

What is CWE-259?

The product contains a hard-coded password, which it uses for its own inbound authentication or for outbound communication to external components.

There are two main variations of a hard-coded password: Inbound: the product contains an authentication mechanism that checks for a hard-coded password. Outbound: the product connects to another system or component, and it contains a hard-coded password for connecting to that component.

CWE-259 is a variant-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-259 definition, reproduced verbatim). Counts and linkage below are Threadlinqs data.

Consequences

  • Access Control — Gain Privileges or Assume Identity. If hard-coded passwords are used, it is almost certain that malicious users can gain access through the account in question.
  • Access Control — Gain Privileges or Assume Identity, Hide Activities, Reduce Maintainability. A hard-coded password typically leads to a significant authentication failure that can be difficult for the system administrator to detect. Once detected, it can be difficult to fix, so the administrator may be forced into disabling the product entirely.

Source: MITRE CWE, common consequences.

How CWE-259 is exploited in the wild

Threadlinqs maps 3 CVEs to CWE-259, published between 2024-09-24 and 2026-09-05. 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 1 critical, 2 medium. The highest EPSS score in the set is 0.6% (CVE-2024-43423), the modelled probability of exploitation in the next 30 days. 3 tracked threats reference CWE-259 directly or through a CVE it covers; the most recent is “Eclypsium InfraTrust Report: Mass Active Exploitation of Network Management Systems (Cisco FMC/ISE CVE-2026-20079, CVE-2026-76460; SonicWall SMA 1000 CVE-2026-83548/83549; Linux Kernel CopyFail CVE-2026-31431)” (2026-09-23). Affected products concentrate in Cisco (1), Dover Fueling Solutions (DFS) (1), Tenda (1).

Vulnerabilities (CVEs)

All 3 CVEs mapped to CWE-259, CISA KEV first, then by CVSS score.

  • CVE-2026-20316 — CISA KEV · CVSS 5.3 medium · published 2026-07-29
  • CVE-2024-43423 — CVSS 9.8 critical · EPSS 0.6% · published 2024-09-24
  • CVE-2026-86150 — CVSS 4.1 medium · EPSS 0.2% · published 2026-09-05

Affected vendors

Threat activity

3 tracked threats cite CWE-259:

Mitigations

  • Architecture and Design: For outbound authentication: store passwords outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible.
  • Architecture and Design: For inbound authentication: Rather than hard-code a default username and password for first time logins, utilize a "first login" mode that requires the user to enter a unique strong password.
  • Architecture and Design: Perform access control checks and limit which entities can access the feature that requires the hard-coded password. For example, a feature might only be enabled through the system console instead of through a network connection.
  • Architecture and Design: For inbound authentication: apply strong one-way hashes to your passwords and store those hashes in a configuration file or database with appropriate access control. That way, theft of the file/database still requires the attacker to try to crack the password. When receiving an incoming password during authentication, take the hash of the password and compare it to the hash that you have saved. Use randomly assigned salts for each separate hash that you generate. This increases the amount of computation that an attacker needs to conduct a brute-force attack, possibly limiting the effectiveness of the rainbow table method.
  • Architecture and Design: For front-end to back-end connections: Three solutions are possible, although none are complete. The first suggestion involves the use of generated passwords which are changed automatically and must be entered at given time intervals by a system administrator. These passwords will be held in memory and only be valid for the time intervals. Next, the passwords used should be limited at the back end to only performing actions valid for the front end, as opposed to having full access. Finally, the messages sent should be tagged and checksummed with time sensitive values so as to prevent replay style attacks.

Source: MITRE CWE, potential mitigations.

Detection methods (MITRE CWE)

  • Manual Analysis: This weakness can be detected using 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.
  • 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.)

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