CWE-168: Improper Handling of Inconsistent Special Elements

BaseDraft

The product does not properly handle input in which an inconsistency exists between two or more special characters or reserved words.

View on MITRE
Back to CWE Lookup

Extended Description

An example of this problem would be if paired characters appear in the wrong order, or if the special characters are not properly nested.

Technical Details

Structure
Simple
Vulnerability Mapping
ALLOWED

Applicable To

Languages
Not Language-Specific
Platforms

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-168 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-168, Improper Handling of Inconsistent Special Elements, 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 Handling of Inconsistent Special Elements

MITRE associates mitigation with Implementation; the listed strategies include Input Validation; recorded impacts include DoS: Crash, Exit, or Restart, Bypass Protection Mechanism, and Hide Activities. Use these source-defined anchors to turn CWE-168 into implementation, review, and verification checks for the affected component.

CWE-168: Improper Handling of Inconsistent Special Elements — MITRE CWE

Triage CWE-168 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-168, Improper Handling of Inconsistent Special Elements, 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-168

Apply MITRE's full root-cause mapping guidance when using CWE-168, Improper Handling of Inconsistent Special Elements. 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-168 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-168, Improper Handling of Inconsistent Special Elements. 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-168: Improper Handling of Inconsistent Special Elements?+

CWE-168: Improper Handling of Inconsistent Special Elements is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product does not properly handle input in which an inconsistency exists between two or more special characters or reserved words. An example of this problem would be if paired characters appear in the wrong order, or if the special characters are not properly nested.

What are the security consequences of Improper Handling of Inconsistent Special Elements?+

If exploited, CWE-168 (Improper Handling of Inconsistent Special Elements) it can compromise Availability, Access Control and Non-Repudiation, leading to outcomes such as DoS: Crash, Exit, or Restart, Bypass Protection Mechanism and Hide Activities.

How do you prevent or mitigate Improper Handling of Inconsistent Special Elements?+

Recommended mitigations for CWE-168 include: Developers should anticipate that inconsistent special elements will be injected/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.

Which programming languages are affected by Improper Handling of Inconsistent Special Elements?+

CWE-168 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

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

A CWE (Common Weakness Enumeration) like CWE-168 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.

Learn More

Find Related CVEs

Search for vulnerabilities that exploit CWE-168

CVE vs CWE: What's the Difference?

Understanding vulnerabilities vs weaknesses

Understanding CVSS Scoring

How vulnerability severity is measured

View Full MITRE Entry

Complete technical details and references

Advertisement