CWE-117: Improper Output Neutralization for Logs

Code Examples & CVEs

Demonstrative Examples

The following web application code attempts to read an integer value from a request object. If the parseInt call fails, then the input is logged with an error message indicating what happened.

If a user submits the string "twenty-one" for val, the following entry is logged:

BadJava

String val = request.getParameter("val");try {                                                     int value = Integer.parseInt(val);                      }catch (NumberFormatException) {log.info("Failed to parse val = " + val);}...

Observed CVE Examples (1)

CVE-2006-4624

Chain: inject fake log entries with fake timestamps using CRLF injection

View Details

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-117 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-117, Improper Output Neutralization for Logs, 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 Output Neutralization for Logs

MITRE associates mitigation with Implementation; the listed strategies include Input Validation, and Output Encoding; documented detection approaches include Automated Static Analysis. Use these source-defined anchors to turn CWE-117 into implementation, review, and verification checks for the affected component.

CWE-117: Improper Output Neutralization for Logs — MITRE CWE

Triage CWE-117 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-117, Improper Output Neutralization for Logs, 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-117

Apply MITRE's full root-cause mapping guidance when using CWE-117, Improper Output Neutralization for Logs. 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-117 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-117, Improper Output Neutralization for Logs. 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-117: Improper Output Neutralization for Logs?+

CWE-117: Improper Output Neutralization for Logs is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.

What are the security consequences of Improper Output Neutralization for Logs?+

If exploited, CWE-117 (Improper Output Neutralization for Logs) it can compromise Integrity, Confidentiality, Availability and Non-Repudiation, leading to outcomes such as Modify Application Data, Hide Activities and Execute Unauthorized Code or Commands.

Which programming languages are affected by Improper Output Neutralization for Logs?+

CWE-117 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Improper Output Neutralization for Logs?+

MITRE documents real CVEs mapped to CWE-117, including CVE-2006-4624. 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-117 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-117: Improper Output Neutralization for Logs

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Detection Methods