CWE-180: Incorrect Behavior Order: Validate Before Canonicalize

Q: What are the security consequences of Incorrect Behavior Order: Validate Before Canonicalize?

If exploited, CWE-180 (Incorrect Behavior Order: Validate Before Canonicalize) it can compromise Access Control, leading to outcomes such as Bypass Protection Mechanism.

Q: Which programming languages are affected by Incorrect Behavior Order: Validate Before Canonicalize?

CWE-180 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

Q: What are real-world examples of Incorrect Behavior Order: Validate Before Canonicalize?

MITRE documents real CVEs mapped to CWE-180, including CVE-2002-0433, CVE-2003-0332, CVE-2002-0802, CVE-2000-0191 and CVE-2004-2363. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.

Q: What is the difference between a CWE and a CVE?

A CWE (Common Weakness Enumeration) like CWE-180 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.

Code Examples & CVEs

Demonstrative Examples

The following code attempts to validate a given input path by checking it against an allowlist and then return the canonical path. In this specific case, the path is considered valid if it starts with the string "/safe_dir/".

The problem with the above code is that the validation step occurs before canonicalization occurs. An attacker could provide an input path of "/safe_dir/../" that would pass the validation step. However, the canonicalization process sees the double dot as a traversal to the parent directory and hence when canonicized the path would become just "/".

BadJava

String path = getInputPath();if (path.startsWith("/safe_dir/")){File f = new File(path);return f.getCanonicalPath();}

GoodJava

String path = getInputPath();File f = new File(path);if (f.getCanonicalPath().startsWith("/safe_dir/")){return f.getCanonicalPath();}

Observed CVE Examples (5)

CVE-2002-0433

List files in web server using "*.ext"

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CVE-2003-0332

Product modifies the first two letters of a filename extension after performing a security check, which allows remote attackers to bypass authentication via a filename with a .ats extension instead of a .hts extension.

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CVE-2002-0802

Database consumes an extra character when processing a character that cannot be converted, which could remove an escape character from the query and make the application subject to SQL injection attacks.

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CVE-2000-0191

Overlaps "fakechild/../realchild"

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CVE-2004-2363

Product checks URI for "<" and other literal characters, but does it before hex decoding the URI, so "%3E" and other sequences are allowed.

View Details

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-180 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-180, Incorrect Behavior Order: Validate Before Canonicalize, 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 Incorrect Behavior Order: Validate Before Canonicalize

MITRE associates mitigation with Implementation; the listed strategies include Input Validation; recorded impacts include Bypass Protection Mechanism. Use these source-defined anchors to turn CWE-180 into implementation, review, and verification checks for the affected component.

CWE-180: Incorrect Behavior Order: Validate Before Canonicalize — MITRE CWE

Triage CWE-180 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-180, Incorrect Behavior Order: Validate Before Canonicalize, 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-180

Apply MITRE's full root-cause mapping guidance when using CWE-180, Incorrect Behavior Order: Validate Before Canonicalize. 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-180 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-180, Incorrect Behavior Order: Validate Before Canonicalize. 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-180: Incorrect Behavior Order: Validate Before Canonicalize?+

CWE-180: Incorrect Behavior Order: Validate Before Canonicalize is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product validates input before it is canonicalized, which prevents the product from detecting data that becomes invalid after the canonicalization step. This can be used by an attacker to bypass the validation and launch attacks that expose weaknesses that would otherwise be prevented, such as injection.

What are the security consequences of Incorrect Behavior Order: Validate Before Canonicalize?+

If exploited, CWE-180 (Incorrect Behavior Order: Validate Before Canonicalize) it can compromise Access Control, leading to outcomes such as Bypass Protection Mechanism.

Which programming languages are affected by Incorrect Behavior Order: Validate Before Canonicalize?+

CWE-180 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 Incorrect Behavior Order: Validate Before Canonicalize?+

MITRE documents real CVEs mapped to CWE-180, including CVE-2002-0433, CVE-2003-0332, CVE-2002-0802, CVE-2000-0191 and CVE-2004-2363. 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-180 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-180: Incorrect Behavior Order: Validate Before Canonicalize

Extended Description

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Detection Methods

Code Examples & CVEs

Demonstrative Examples

Observed CVE Examples (5)

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-180 with SSDF evidence

Apply Input Validation controls for Incorrect Behavior Order: Validate Before Canonicalize

Triage CWE-180 against known exploitation evidence

Apply precise root-cause mapping to CWE-180

Validate CWE-180 with root-cause mapping checks

Frequently Asked Questions

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