CWE-123: Write-what-where Condition

BaseDraftExploit Likelihood: High

Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.

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Technical Details

Structure
Simple
Vulnerability Mapping
ALLOWED

Applicable To

Languages
CC++Memory-Unsafe
Platforms

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-123 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-123, Write-what-where Condition, 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 Language Selection controls for Write-what-where Condition

MITRE associates mitigation with Architecture and Design, and Operation; the listed strategies include Language Selection; documented detection approaches include Automated Static Analysis, and Automated Dynamic Analysis. Use these source-defined anchors to turn CWE-123 into implementation, review, and verification checks for the affected component.

CWE-123: Write-what-where Condition — MITRE CWE

Triage CWE-123 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-123, Write-what-where Condition, 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-123

Apply MITRE's full root-cause mapping guidance when using CWE-123, Write-what-where Condition. 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-123 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-123, Write-what-where Condition. 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-123: Write-what-where Condition?+

CWE-123: Write-what-where Condition is a Common Weakness Enumeration (CWE) entry maintained by MITRE. Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.

What are the security consequences of Write-what-where Condition?+

If exploited, CWE-123 (Write-what-where Condition) it can compromise Integrity, Confidentiality, Availability, Access Control and Other, leading to outcomes such as Modify Memory, Execute Unauthorized Code or Commands, Gain Privileges or Assume Identity, DoS: Crash, Exit, or Restart, Bypass Protection Mechanism and Other.

How do you prevent or mitigate Write-what-where Condition?+

Recommended mitigations for CWE-123 include: Use a language that provides appropriate memory abstractions. Use OS-level preventative functionality integrated after the fact. Not a complete solution.

Which programming languages are affected by Write-what-where Condition?+

CWE-123 commonly affects C, C++ and Memory-Unsafe. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Write-what-where Condition?+

MITRE documents real CVEs mapped to CWE-123, including CVE-2019-19911 and CVE-2022-0545. 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-123 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.

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