CWE-1287: Improper Validation of Specified Type of Input

Extended Description

When input does not comply with the expected type, attackers could trigger unexpected errors, cause incorrect actions to take place, or exploit latent vulnerabilities that would not be possible if the input conformed with the expected type. This weakness can appear in type-unsafe programming languages, or in programming languages that support casting or conversion of an input to another type.

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-1287 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-1287, Improper Validation of Specified Type of Input, 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 Improper Validation of Specified Type of Input

MITRE associates mitigation with Implementation; the listed strategies include Input Validation; recorded impacts include Varies by Context. Use these source-defined anchors to turn CWE-1287 into implementation, review, and verification checks for the affected component.

CWE-1287: Improper Validation of Specified Type of Input — MITRE CWE

Triage CWE-1287 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-1287, Improper Validation of Specified Type of Input, 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-1287

Apply MITRE's full root-cause mapping guidance when using CWE-1287, Improper Validation of Specified Type of Input. 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-1287 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-1287, Improper Validation of Specified Type of Input. 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-1287: Improper Validation of Specified Type of Input?+

CWE-1287: Improper Validation of Specified Type of Input is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type. When input does not comply with the expected type, attackers could trigger unexpected errors, cause incorrect actions to take place, or exploit latent vulnerabilities that would not be possible if the input conformed with the expected type. This weakness can appear in type-unsafe programming languages, or in programming languages that support casting or conversion of an input to another type.

What are the security consequences of Improper Validation of Specified Type of Input?+

If exploited, CWE-1287 (Improper Validation of Specified Type of Input) it can compromise Other, leading to outcomes such as Varies by Context.

Which programming languages are affected by Improper Validation of Specified Type of Input?+

CWE-1287 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 Improper Validation of Specified Type of Input?+

MITRE documents real CVEs mapped to CWE-1287, including CVE-2024-37032 and CVE-2008-2223. 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-1287 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-1287: Improper Validation of Specified Type of Input

Extended Description

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Detection Methods

Code Examples & CVEs

Observed CVE Examples (2)

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