The product compares two entities in a security-relevant context, but the comparison is incorrect.
View on MITREThis Pillar covers several possibilities: the comparison checks one factor incorrectly; the comparison should consider multiple factors, but it does not check at least one of those factors at all; the comparison checks the wrong factor.
When the comparison is incorrect, it may lead to resultant weaknesses.
No mitigation information available for this CWE.
No detection method information available for this CWE.
Consider an application in which Truck objects are defined to be the same if they have the same make, the same model, and were manufactured in the same year.
Here, the equals() method only checks the make and model of the Truck objects, but the year of manufacture is not included.
public class Truck { private String make;private String model;private int year; public boolean equals(Object o) { if (o == null) return false;if (o == this) return true;if (!(o instanceof Truck)) return false; Truck t = (Truck) o; return (this.make.equals(t.getMake()) && this.model.equals(t.getModel())); } }This example defines a fixed username and password. The AuthenticateUser() function is intended to accept a username and a password from an untrusted user, and check to ensure that it matches the username and password. If the username and password match, AuthenticateUser() is intended to indicate that authentication succeeded.
In AuthenticateUser(), the strncmp() call uses the string length of an attacker-provided inPass parameter in order to determine how many characters to check in the password. So, if the attacker only provides a password of length 1, the check will only examine the first byte of the application's password before determining success.
/* Ignore CWE-259 (hard-coded password) and CWE-309 (use of password system for authentication) for this example. */ char *username = "admin";char *pass = "password"; int AuthenticateUser(char *inUser, char *inPass) {if (strncmp(username, inUser, strlen(inUser))) {logEvent("Auth failure of username using strlen of inUser");return(AUTH_FAIL);}if (! strncmp(pass, inPass, strlen(inPass))) {logEvent("Auth success of password using strlen of inUser");return(AUTH_SUCCESS);}else {logEvent("Auth fail of password using sizeof");return(AUTH_FAIL);}} int main (int argc, char **argv) { int authResult;if (argc < 3) {ExitError("Usage: Provide a username and password");}authResult = AuthenticateUser(argv[1], argv[2]);if (authResult == AUTH_SUCCESS) {DoAuthenticatedTask(argv[1]);}else {ExitError("Authentication failed");}}Chain: Python-based HTTP Proxy server uses the wrong boolean operators (CWE-480) causing an incorrect comparison (CWE-697) that identifies an authN failure if all three conditions are met instead of only one, allowing bypass of the proxy authentication (CWE-1390)
View DetailsChain: Proxy uses a substring search instead of parsing the Transfer-Encoding header (CWE-697), allowing request splitting (CWE-113) and cache poisoning
View DetailsProxy performs incorrect comparison of request headers, leading to infoleak
View DetailsNo relationship information available for this CWE.
Additional facts reviewed against primary or authoritative security sources.
Documented detection approaches include Automated Static Analysis; recorded impacts include Varies by Context; the entry maps to CAPEC-10, CAPEC-120, CAPEC-14, and CAPEC-15. Use these source-defined anchors to turn CWE-697 into implementation, review, and verification checks for the affected component.
CWE-697: Incorrect Comparison — MITRE CWEUse NIST SSDF practices to make prevention of CWE-697, Incorrect Comparison, an explicit development outcome. Translate the CWE definition into security requirements and design constraints, choose safer implementation patterns and toolchain checks, and define acceptance evidence before release. Feed every confirmed occurrence back into the requirements, design review, and coding rules so the same root cause is removed across the product rather than patched in one location.
NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and TechnologyUse CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-697, Incorrect Comparison, 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 AgencyApply MITRE's full root-cause mapping guidance when using CWE-697, Incorrect Comparison. 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 CWEApply MITRE's root-cause mapping quick tips to CWE-697, Incorrect Comparison. 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 CWECWE-697: Incorrect Comparison is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product compares two entities in a security-relevant context, but the comparison is incorrect. This Pillar covers several possibilities: the comparison checks one factor incorrectly; the comparison should consider multiple factors, but it does not check at least one of those factors at all; the comparison checks the wrong factor.
If exploited, CWE-697 (Incorrect Comparison) it can compromise Other, leading to outcomes such as Varies by Context.
CWE-697 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.
MITRE documents real CVEs mapped to CWE-697, including CVE-2021-3116, CVE-2020-15811 and CVE-2016-10003. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
A CWE (Common Weakness Enumeration) like CWE-697 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.