Collapse of Data into Unsafe Value (4.19.1)
Weakness ID: 182
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilitiesAbstraction: Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Description
The product filters data in a way that causes it to be reduced or "collapsed" into an unsafe value that violates an expected security property.
Common Consequences
This table specifies different individual consequences
associated with the weakness. The Scope identifies the application security area that is
violated, while the Impact describes the negative technical impact that arises if an
adversary succeeds in exploiting this weakness. The Likelihood provides information about
how likely the specific consequence is expected to be seen relative to the other
consequences in the list. For example, there may be high likelihood that a weakness will be
exploited to achieve a certain impact, but a low likelihood that it will be exploited to
achieve a different impact.
| Impact | Details |
|---|---|
|
Bypass Protection Mechanism |
Scope: Access Control |
Potential Mitigations
| Phase(s) | Mitigation |
|---|---|
|
Architecture and Design |
Strategy: Input Validation Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names. |
|
Implementation |
Strategy: Input Validation Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. |
|
Implementation |
Strategy: Input Validation Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked. |
|
Canonicalize the name to match that of the file system's representation of the name. This can sometimes be achieved with an available API (e.g. in Win32 the GetFullPathName function). |
Relationships
This table shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to
similar items that may exist at higher and lower levels of abstraction. In addition,
relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user
may want to explore.
Relevant to the view "Research Concepts" (View-1000)
| Nature | Type | ID | Name |
|---|---|---|---|
| ChildOf |
Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.
|
707 | Improper Neutralization |
| CanFollow |
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
|
185 | Incorrect Regular Expression |
| CanPrecede |
Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
|
33 | Path Traversal: '....' (Multiple Dot) |
| CanPrecede |
Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
|
34 | Path Traversal: '....//' |
| CanPrecede |
Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
|
35 | Path Traversal: '.../...//' |
Relevant to the view "Software Development" (View-699)
| Nature | Type | ID | Name |
|---|---|---|---|
| MemberOf |
Category - a CWE entry that contains a set of other entries that share a common characteristic.
|
19 | Data Processing Errors |
Modes
Of Introduction
The different Modes of Introduction provide information
about how and when this
weakness may be introduced. The Phase identifies a point in the life cycle at which
introduction
may occur, while the Note provides a typical scenario related to introduction during the
given
phase.
| Phase | Note |
|---|---|
| Implementation |
Applicable Platforms
This listing shows possible areas for which the given
weakness could appear. These
may be for specific named Languages, Operating Systems, Architectures, Paradigms,
Technologies,
or a class of such platforms. The platform is listed along with how frequently the given
weakness appears for that instance.
| Languages |
Class: Not Language-Specific (Undetermined Prevalence) |
| Technologies |
Class: Not Technology-Specific (Undetermined Prevalence) |
Selected Observed
Examples
Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.
| Reference | Description |
|---|---|
|
"/.////" in pathname collapses to absolute path. |
|
|
"/.//..//////././" is collapsed into "/.././" after ".." and "//" sequences are removed. |
|
|
".../...//" collapsed to "..." due to removal of "./" in web server. |
|
|
chain: HTTP server protects against ".." but allows "." variants such as "////./../.../". If the server removes "/.." sequences, the result would collapse into an unsafe value "////../" (CWE-182). |
|
|
MFV. Regular expression intended to protect against directory traversal reduces ".../...//" to "../". |
|
|
XSS protection mechanism strips a <script> sequence that is nested in another <script> sequence. |
Weakness Ordinalities
| Ordinality | Description |
|---|---|
|
Primary |
(where the weakness exists independent of other weaknesses) |
Detection
Methods
| Method | Details |
|---|---|
|
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.) Effectiveness: High |
Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that
reference this weakness as a member. This information is often useful in understanding where a
weakness fits within the context of external information sources.
Vulnerability Mapping Notes
| Usage |
ALLOWED
(this CWE ID may be used to map to real-world vulnerabilities) |
| Reason | Acceptable-Use |
|
Rationale |
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities. |
|
Comments |
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction. |
Notes
Relationship
Overlaps regular expressions, although an implementation might not necessarily use regexp's.
Taxonomy
Mappings
| Mapped Taxonomy Name | Node ID | Fit | Mapped Node Name |
|---|---|---|---|
| PLOVER | Collapse of Data into Unsafe Value | ||
| The CERT Oracle Secure Coding Standard for Java (2011) | IDS11-J | Eliminate noncharacter code points before validation |
References
| [REF-62] | Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 8, "Character Stripping Vulnerabilities", Page 437. 1st Edition. Addison Wesley. 2006. |
Content
History
| Submissions |
||
|---|---|---|
| Submission Date | Submitter | Organization |
|
2006-07-19
(CWE Draft 3, 2006-07-19) |
PLOVER | |
 Modifications |
||
| Modification Date | Modifier | Organization |
|
2025-12-11
(CWE 4.19, 2025-12-11) |
CWE Content Team | MITRE |
| updated Applicable_Platforms, Weakness_Ordinalities | ||
|
2025-04-03
(CWE 4.17, 2025-04-03) |
CWE Content Team | MITRE |
| updated Relationships | ||
| 2023-06-29 | CWE Content Team | MITRE |
| updated Mapping_Notes | ||
| 2023-04-27 | CWE Content Team | MITRE |
| updated Detection_Factors, Relationships | ||
| 2023-01-31 | CWE Content Team | MITRE |
| updated Description | ||
| 2020-06-25 | CWE Content Team | MITRE |
| updated Potential_Mitigations | ||
| 2020-02-24 | CWE Content Team | MITRE |
| updated Potential_Mitigations, Relationships | ||
| 2019-01-03 | CWE Content Team | MITRE |
| updated Relationships, Taxonomy_Mappings | ||
| 2017-11-08 | CWE Content Team | MITRE |
| updated Applicable_Platforms, Relevant_Properties | ||
| 2014-07-30 | CWE Content Team | MITRE |
| updated Relationships | ||
| 2012-10-30 | CWE Content Team | MITRE |
| updated Potential_Mitigations | ||
| 2012-05-11 | CWE Content Team | MITRE |
| updated References, Relationships, Taxonomy_Mappings | ||
| 2011-06-01 | CWE Content Team | MITRE |
| updated Common_Consequences, Relationships, Taxonomy_Mappings | ||
| 2011-03-29 | CWE Content Team | MITRE |
| updated Potential_Mitigations | ||
| 2010-12-13 | CWE Content Team | MITRE |
| updated Relationships | ||
| 2010-06-21 | CWE Content Team | MITRE |
| updated Description, Observed_Examples | ||
| 2009-07-27 | CWE Content Team | MITRE |
| updated Potential_Mitigations | ||
| 2009-03-10 | CWE Content Team | MITRE |
| updated Relationships | ||
| 2008-11-24 | CWE Content Team | MITRE |
| updated Observed_Examples | ||
| 2008-09-08 | CWE Content Team | MITRE |
| updated Description, Relationships, Relationship_Notes, Relevant_Properties, Taxonomy_Mappings | ||
| 2008-07-01 | Eric Dalci | Cigital |
| updated Potential_Mitigations, Time_of_Introduction | ||