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Home > CWE List > CWE-823: Use of Out-of-range Pointer Offset (4.17)  
ID

CWE-823: Use of Out-of-range Pointer Offset

Weakness ID: 823
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: 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.
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+ Description
The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.
+ Extended Description

While a pointer can contain a reference to any arbitrary memory location, a program typically only intends to use the pointer to access limited portions of memory, such as contiguous memory used to access an individual array.

Programs may use offsets in order to access fields or sub-elements stored within structured data. The offset might be out-of-range if it comes from an untrusted source, is the result of an incorrect calculation, or occurs because of another error.

If an attacker can control or influence the offset so that it points outside of the intended boundaries of the structure, then the attacker may be able to read or write to memory locations that are used elsewhere in the product. As a result, the attack might change the state of the product as accessed through program variables, cause a crash or instable behavior, and possibly lead to code execution.

+ Alternate Terms
Untrusted pointer offset
This term is narrower than the concept of "out-of-range" offset, since the offset might be the result of a calculation or other error that does not depend on any externally-supplied values.
+ Common Consequences
Section HelpThis 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

Read Memory

Scope: Confidentiality

If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.

DoS: Crash, Exit, or Restart

Scope: Availability

If the untrusted pointer references a memory location that is not accessible to the program, or points to a location that is "malformed" or larger than expected by a read or write operation, the application may terminate unexpectedly.

Execute Unauthorized Code or Commands; Modify Memory

Scope: Integrity, Confidentiality, Availability

If the untrusted pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
+ Relationships
Section Help 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 Class 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. 119 Improper Restriction of Operations within the Bounds of a Memory Buffer
CanFollow Variant 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. 129 Improper Validation of Array Index
CanPrecede 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. 125 Out-of-bounds Read
CanPrecede 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. 787 Out-of-bounds Write
+ Relevant to the view "Software Development" (View-699)
Nature Type ID Name
MemberOf Category Category - a CWE entry that contains a set of other entries that share a common characteristic. 465 Pointer Issues
+ Relevant to the view "CISQ Quality Measures (2020)" (View-1305)
Nature Type ID Name
ChildOf Class 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. 119 Improper Restriction of Operations within the Bounds of a Memory Buffer
+ Relevant to the view "CISQ Data Protection Measures" (View-1340)
Nature Type ID Name
ChildOf Class 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. 119 Improper Restriction of Operations within the Bounds of a Memory Buffer
+ 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
Invalid offset in undocumented opcode leads to memory corruption.
Multimedia player uses untrusted value from a file when using file-pointer calculations.
Spreadsheet program processes a record with an invalid size field, which is later used as an offset.
Instant messaging library does not validate an offset value specified in a packet.
Language interpreter does not properly handle invalid offsets in JPEG image, leading to out-of-bounds memory access and crash.
negative offset leads to out-of-bounds read
untrusted offset in kernel
"blind trust" of an offset value while writing heap memory allows corruption of function pointer,leading to code execution
negative value (signed) causes pointer miscalculation
signed values cause incorrect pointer calculation
values used as pointer offsets
a return value from a function is sign-extended if the value is signed, then used as an offset for pointer arithmetic
portions of a GIF image used as offsets, causing corruption of an object pointer.
invalid numeric field leads to a free of arbitrary memory locations, then code execution.
large number of elements leads to a free of an arbitrary address
array index issue (CWE-129) with negative offset, used to dereference a function pointer
"buffer seek" value - basically an offset?
+ 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
Section HelpThis 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.
Nature Type ID Name
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1399 Comprehensive Categorization: Memory Safety
+ 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

Terminology

Many weaknesses related to pointer dereferences fall under the general term of "memory corruption" or "memory safety." As of September 2010, there is no commonly-used terminology that covers the lower-level variants.

Maintenance

There are close relationships between incorrect pointer dereferences and other weaknesses related to buffer operations. There may not be sufficient community agreement regarding these relationships. Further study is needed to determine when these relationships are chains, composites, perspective/layering, or other types of relationships. As of September 2010, most of the relationships are being captured as chains.
+ References
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Pointer Arithmetic", Page 277. 1st Edition. Addison Wesley. 2006.
+ Content History
+ Submissions
Submission Date Submitter Organization
2010-09-22
(CWE 1.10, 2010-09-27) 		CWE Content Team MITRE
+ Modifications
Modification Date Modifier Organization
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
2022-04-28 CWE Content Team MITRE
updated Research_Gaps
2020-12-10 CWE Content Team MITRE
updated Relationships
2020-08-20 CWE Content Team MITRE
updated Relationships
2020-02-24 CWE Content Team MITRE
updated Relationships
2019-06-20 CWE Content Team MITRE
updated Related_Attack_Patterns
2012-05-11 CWE Content Team MITRE
updated References
2011-06-01 CWE Content Team MITRE
updated Common_Consequences
Page Last Updated: April 03, 2025
 

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