CWE-192: Integer Coercion Error

Extended Description

Several flaws fall under the category of integer coercion errors. For the most part, these errors in and of themselves result only in availability and data integrity issues. However, in some circumstances, they may result in other, more complicated security related flaws, such as buffer overflow conditions.

Code Examples & CVEs

Demonstrative Examples

The following code is intended to read an incoming packet from a socket and extract one or more headers.

The code performs a check to make sure that the packet does not contain too many headers. However, numHeaders is defined as a signed int, so it could be negative. If the incoming packet specifies a value such as -3, then the malloc calculation will generate a negative number (say, -300 if each header can be a maximum of 100 bytes). When this result is provided to malloc(), it is first converted to a size_t type. This conversion then produces a large value such as 4294966996, which may cause malloc() to fail or to allocate an extremely large amount of memory (CWE-195). With the appropriate negative numbers, an attacker could trick malloc() into using a very small positive number, which then allocates a buffer that is much smaller than expected, potentially leading to a buffer overflow.

BadC

DataPacket *packet;int numHeaders;PacketHeader *headers;                      sock=AcceptSocketConnection();ReadPacket(packet, sock);numHeaders =packet->headers;                      if (numHeaders > 100) {ExitError("too many headers!");}headers = malloc(numHeaders * sizeof(PacketHeader);ParsePacketHeaders(packet, headers);

The following code reads a maximum size and performs validation on that size. It then performs a strncpy, assuming it will not exceed the boundaries of the array. While the use of "short s" is forced in this particular example, short int's are frequently used within real-world code, such as code that processes structured data.

This code first exhibits an example of CWE-839, allowing "s" to be a negative number. When the negative short "s" is converted to an unsigned integer, it becomes an extremely large positive integer. When this converted integer is used by strncpy() it will lead to a buffer overflow (CWE-119).

BadC

int GetUntrustedInt () {return(0x0000FFFF);}                      void main (int argc, char **argv) {                         char path[256];char *input;int i;short s;unsigned int sz;                            i = GetUntrustedInt();s = i;/* s is -1 so it passes the safety check - CWE-697 */if (s > 256) {DiePainfully("go away!\n");}                            /* s is sign-extended and saved in sz */sz = s;                            /* output: i=65535, s=-1, sz=4294967295 - your mileage may vary */printf("i=%d, s=%d, sz=%u\n", i, s, sz);                            input = GetUserInput("Enter pathname:");                            /* strncpy interprets s as unsigned int, so it's treated as MAX_INT(CWE-195), enabling buffer overflow (CWE-119) */strncpy(path, input, s);path[255] = '\0'; /* don't want CWE-170 */printf("Path is: %s\n", path);                      }

Observed CVE Examples (1)

CVE-2022-2639

Chain: integer coercion error (CWE-192) prevents a return value from indicating an error, leading to out-of-bounds write (CWE-787)

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Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-192 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-192, Integer Coercion Error, 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 Integer Coercion Error during Requirements

MITRE associates mitigation with Requirements, Architecture and Design, and Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory), DoS: Crash, Exit, or Restart, Execute Unauthorized Code or Commands, and Other. Use these source-defined anchors to turn CWE-192 into implementation, review, and verification checks for the affected component.

CWE-192: Integer Coercion Error — MITRE CWE

Triage CWE-192 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-192, Integer Coercion Error, 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-192

Apply MITRE's full root-cause mapping guidance when using CWE-192, Integer Coercion Error. 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-192 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-192, Integer Coercion Error. 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-192: Integer Coercion Error?+

CWE-192: Integer Coercion Error is a Common Weakness Enumeration (CWE) entry maintained by MITRE. Integer coercion refers to a set of flaws pertaining to the type casting, extension, or truncation of primitive data types. Several flaws fall under the category of integer coercion errors. For the most part, these errors in and of themselves result only in availability and data integrity issues. However, in some circumstances, they may result in other, more complicated security related flaws, such as buffer overflow conditions.

What are the security consequences of Integer Coercion Error?+

If exploited, CWE-192 (Integer Coercion Error) it can compromise Availability, Integrity, Confidentiality and Other, leading to outcomes such as DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory), DoS: Crash, Exit, or Restart, Execute Unauthorized Code or Commands and Other.

How do you prevent or mitigate Integer Coercion Error?+

Recommended mitigations for CWE-192 include: A language which throws exceptions on ambiguous data casts might be chosen. Design objects and program flow such that multiple or complex casts are unnecessary Ensure that any data type casting that you must used is entirely understood in order to reduce the plausibility of error in use.

Which programming languages are affected by Integer Coercion Error?+

CWE-192 commonly affects C, C++, Java and C#. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Integer Coercion Error?+

MITRE documents real CVEs mapped to CWE-192, including CVE-2022-2639. 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-192 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-192: Integer Coercion Error

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Code Examples & CVEs

Demonstrative Examples

Observed CVE Examples (1)

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-192 with SSDF evidence

Address Integer Coercion Error during Requirements

Triage CWE-192 against known exploitation evidence

Apply precise root-cause mapping to CWE-192

Validate CWE-192 with root-cause mapping checks

Frequently Asked Questions

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