CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable

Extended Description

Information stored in an environment variable can be accessible by other processes with the execution context, including child processes that dependencies are executed in, or serverless functions in cloud environments. An environment variable's contents can also be inserted into messages, headers, log files, or other outputs. Often these other dependencies have no need to use the environment variable in question. A weakness that discloses environment variables could expose this information.

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-526 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-526, Cleartext Storage of Sensitive Information in an Environment Variable, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Cleartext Storage of Sensitive Information in an Environment Variable during Architecture and Design

MITRE associates mitigation with Architecture and Design, and Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include Read Application Data. Use these source-defined anchors to turn CWE-526 into implementation, review, and verification checks for the affected component.

CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable — MITRE CWE

Triage CWE-526 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-526, Cleartext Storage of Sensitive Information in an Environment Variable, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-526

Apply MITRE's full root-cause mapping guidance when using CWE-526, Cleartext Storage of Sensitive Information in an Environment Variable. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-526 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-526, Cleartext Storage of Sensitive Information in an Environment Variable. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable?+

CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product uses an environment variable to store unencrypted sensitive information. Information stored in an environment variable can be accessible by other processes with the execution context, including child processes that dependencies are executed in, or serverless functions in cloud environments. An environment variable's contents can also be inserted into messages, headers, log files, or other outputs. Often these other dependencies have no need to use the environment variable in question. A weakness that discloses environment variables could expose this information.

What are the security consequences of Cleartext Storage of Sensitive Information in an Environment Variable?+

If exploited, CWE-526 (Cleartext Storage of Sensitive Information in an Environment Variable) it can compromise Confidentiality, leading to outcomes such as Read Application Data.

How do you prevent or mitigate Cleartext Storage of Sensitive Information in an Environment Variable?+

Recommended mitigations for CWE-526 include: Encrypt information stored in the environment variable to protect it from being exposed to an unauthorized user. If encryption is not feasible or is considered too expensive for the business use of the application, then consider using a properly protected configuration file instead of an environment variable. It should be understood that unencrypted information in a config file is also not guaranteed to be protected, but it is still a better choice, because it reduces attack surface related to weaknesses such as CWE-214. In some settings, vaults might be a feasible option for safer data transfer. Users should be notified of the business choice made to not protect the sensitive information through encryption. If the environment variable is not necessary for the desired behavior, then remove it entirely, or clear it to an empty value.

Which programming languages are affected by Cleartext Storage of Sensitive Information in an Environment Variable?+

CWE-526 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Cleartext Storage of Sensitive Information in an Environment Variable?+

MITRE documents real CVEs mapped to CWE-526, including CVE-2022-43691, CVE-2022-27195 and CVE-2022-25264. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-526 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable

Extended Description

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Observed CVE Examples (3)

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