CWE-1236: Improper Neutralization of Formula Elements in a CSV File

BaseIncomplete

The product saves user-provided information into a Comma-Separated Value (CSV) file, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as a command when the file is opened by a spreadsheet product.

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Technical Details

Structure
Simple
Vulnerability Mapping
ALLOWED

Applicable To

Languages
Not Language-Specific
Platforms
Not OS-Specific

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-1236 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-1236, Improper Neutralization of Formula Elements in a CSV File, 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 Improper Neutralization of Formula Elements in a CSV File during Implementation

MITRE associates mitigation with Implementation, and Architecture and Design; documented detection approaches include Automated Static Analysis; recorded impacts include Read Application Data, and Execute Unauthorized Code or Commands. Use these source-defined anchors to turn CWE-1236 into implementation, review, and verification checks for the affected component.

CWE-1236: Improper Neutralization of Formula Elements in a CSV File — MITRE CWE

Triage CWE-1236 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-1236, Improper Neutralization of Formula Elements in a CSV File, 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-1236

Apply MITRE's full root-cause mapping guidance when using CWE-1236, Improper Neutralization of Formula Elements in a CSV File. 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-1236 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-1236, Improper Neutralization of Formula Elements in a CSV File. 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-1236: Improper Neutralization of Formula Elements in a CSV File?+

CWE-1236: Improper Neutralization of Formula Elements in a CSV File is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product saves user-provided information into a Comma-Separated Value (CSV) file, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as a command when the file is opened by a spreadsheet product.

What are the security consequences of Improper Neutralization of Formula Elements in a CSV File?+

If exploited, CWE-1236 (Improper Neutralization of Formula Elements in a CSV File) it can compromise Confidentiality, leading to outcomes such as Read Application Data and Execute Unauthorized Code or Commands.

How do you prevent or mitigate Improper Neutralization of Formula Elements in a CSV File?+

Recommended mitigations for CWE-1236 include: When generating CSV output, ensure that formula-sensitive metacharacters are effectively escaped or removed from all data before storage in the resultant CSV. Risky characters include '=' (equal), '+' (plus), '-' (minus), and '@' (at). If a field starts with a formula character, prepend it with a ' (single apostrophe), which prevents Excel from executing the formula. Certain implementations of spreadsheet software might disallow formulas from executing if the file is untrusted, or if the file is not authored by the current user.

Which programming languages are affected by Improper Neutralization of Formula Elements in a CSV File?+

CWE-1236 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 Neutralization of Formula Elements in a CSV File?+

MITRE documents real CVEs mapped to CWE-1236, including CVE-2019-12134, CVE-2019-4521 and CVE-2019-17661. 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-1236 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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