The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

What CVEs are caused by CWE-191?

251 recorded CVEs are attributed to CWE-191, including CVE-2014-0497, CVE-2022-1698, CVE-2026-37534. 1 are listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.

How is CWE-191 detected?

Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

What are the consequences of CWE-191?

Exploiting CWE-191 can lead to: DoS: Crash, Exit, or Restart, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory), DoS: Instability, Modify Memory, Execute Unauthorized Code or Commands.

Is CWE-191 actively exploited?

Yes. 1 CWE-191 vulnerabilities are in CISA's KEV catalog of actively exploited flaws, out of 251 recorded CVEs.

CWE-191: Integer Underflow (Wrap or Wraparound)

251 recorded CVEs are caused by CWE-191 (Integer Underflow (Wrap or Wraparound)), including 1 in CISA's KEV (Known Exploited Vulnerabilities) catalog. KEVs are shown first. 53 new CWE-191 CVEs have been recorded so far in 2026 (61 in 2025).

Code examples

Illustrative examples from MITRE showing how the weakness appears in code.

The following example subtracts from a 32 bit signed integer.

Vulnerable example

#include <stdio.h>

The example has an integer underflow. The value of i is already at the lowest negative value possible, so after subtracting 1, the new value of i is 2147483647.

This code performs a stack allocation based on a length calculation.

Vulnerable example

int a = 5, b = 6;

CWE-191: Integer Underflow (Wrap or Wraparound)

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

Applies to

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Terminology & mappings

Alternate terms

Mapped taxonomies

Frequently asked questions

What is CWE-191?

What CVEs are caused by CWE-191?

How is CWE-191 detected?

What are the consequences of CWE-191?

Is CWE-191 actively exploited?

References

Stay ahead of CWE-191

Overview

Real-world CVEs

Common consequences

How it happens

When it is introduced

Applies to

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Related weaknesses

Parent

Terminology & mappings

Alternate terms

Mapped taxonomies

Frequently asked questions

What is CWE-191?

What CVEs are caused by CWE-191?

How is CWE-191 detected?

What are the consequences of CWE-191?

Is CWE-191 actively exploited?

References

Stay ahead of CWE-191