CWE-174: Double Decoding of the Same Data

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-174 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-174, Double Decoding of the Same Data, 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

Apply Input Validation controls for Double Decoding of the Same Data

MITRE associates mitigation with Architecture and Design, and Implementation; the listed strategies include Input Validation, and Output Encoding; recorded impacts include Bypass Protection Mechanism, Execute Unauthorized Code or Commands, and Varies by Context. Use these source-defined anchors to turn CWE-174 into implementation, review, and verification checks for the affected component.

CWE-174: Double Decoding of the Same Data — MITRE CWE

Triage CWE-174 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-174, Double Decoding of the Same Data, 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-174

Apply MITRE's full root-cause mapping guidance when using CWE-174, Double Decoding of the Same Data. 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-174 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-174, Double Decoding of the Same Data. 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-174: Double Decoding of the Same Data?+

CWE-174: Double Decoding of the Same Data is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product decodes the same input twice, which can limit the effectiveness of any protection mechanism that occurs in between the decoding operations.

What are the security consequences of Double Decoding of the Same Data?+

If exploited, CWE-174 (Double Decoding of the Same Data) it can compromise Access Control, Confidentiality, Availability, Integrity and Other, leading to outcomes such as Bypass Protection Mechanism, Execute Unauthorized Code or Commands and Varies by Context.

Which programming languages are affected by Double Decoding of the Same Data?+

CWE-174 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 Double Decoding of the Same Data?+

MITRE documents real CVEs mapped to CWE-174, including CVE-2004-1315, CVE-2004-1939, CVE-2001-0333, CVE-2004-1938 and CVE-2005-1945. 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-174 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-174: Double Decoding of the Same Data

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Detection Methods

Code Examples & CVEs

Observed CVE Examples (6)

CWE Relationships

Parent Weaknesses