CWE-471: Modification of Assumed-Immutable Data (MAID)

Code Examples & CVEs

Demonstrative Examples

In the code excerpt below, an array returned by a Java method is modified despite the fact that arrays are mutable.

BadJava

String[] colors = car.getAllPossibleColors();colors[0] = "Red";

Observed CVE Examples (2)

CVE-2002-1757

Relies on $PHP_SELF variable for authentication.

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CVE-2005-1905

Gain privileges by modifying assumed-immutable code addresses that are accessed by a driver.

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Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-471 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-471, Modification of Assumed-Immutable Data (MAID), 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 Modification of Assumed-Immutable Data (MAID) during Architecture and Design

MITRE associates mitigation with Architecture and Design, Operation, and Implementation; recorded impacts include Modify Application Data, and Unexpected State; the entry maps to CAPEC-384, CAPEC-385, CAPEC-386, and CAPEC-387. Use these source-defined anchors to turn CWE-471 into implementation, review, and verification checks for the affected component.

CWE-471: Modification of Assumed-Immutable Data (MAID) — MITRE CWE

Triage CWE-471 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-471, Modification of Assumed-Immutable Data (MAID), 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-471

Apply MITRE's full root-cause mapping guidance when using CWE-471, Modification of Assumed-Immutable Data (MAID). 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-471 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-471, Modification of Assumed-Immutable Data (MAID). 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-471: Modification of Assumed-Immutable Data (MAID)?+

CWE-471: Modification of Assumed-Immutable Data (MAID) is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product does not properly protect an assumed-immutable element from being modified by an attacker. This occurs when a particular input is critical enough to the functioning of the application that it should not be modifiable at all, but it is. Certain resources are often assumed to be immutable when they are not, such as hidden form fields in web applications, cookies, and reverse DNS lookups.

What are the security consequences of Modification of Assumed-Immutable Data (MAID)?+

If exploited, CWE-471 (Modification of Assumed-Immutable Data (MAID)) it can compromise Integrity, leading to outcomes such as Modify Application Data and Unexpected State.

How do you prevent or mitigate Modification of Assumed-Immutable Data (MAID)?+

Recommended mitigations for CWE-471 include: When the data is stored or transmitted through untrusted sources that could modify the data, implement integrity checks to detect unauthorized modification, or store/transmit the data in a trusted location that is free from external influence.

Which programming languages are affected by Modification of Assumed-Immutable Data (MAID)?+

CWE-471 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 Modification of Assumed-Immutable Data (MAID)?+

MITRE documents real CVEs mapped to CWE-471, including CVE-2002-1757 and CVE-2005-1905. 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-471 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-471: Modification of Assumed-Immutable Data (MAID)

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