CWE-126 Detail

CWE-126

Buffer Over-read
Draft
2006-07-19
00h00 +00:00
2025-04-03
00h00 +00:00
CWE Mitre.org
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Name: Buffer Over-read

The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

General Informations

Modes Of Introduction

Implementation

Applicable Platforms

Language

Name: C (Undetermined)
Name: C++ (Undetermined)

Common Consequences

Scope Impact Likelihood
ConfidentialityRead Memory
ConfidentialityBypass Protection Mechanism

Note: By reading out-of-bounds memory, an attacker might be able to get secret values, such as memory addresses, which can be bypass protection mechanisms such as ASLR in order to improve the reliability and likelihood of exploiting a separate weakness to achieve code execution instead of just denial of service.
Availability
Integrity		DoS: Crash, Exit, or Restart

Note: An attacker might be able to cause a crash or other denial of service by causing the product to read a memory location that is not allowed (such as a segmentation fault), or to cause other conditions in which the read operation returns more data than is expected.

Observed Examples

References Description

CVE-2022-1733

Text editor has out-of-bounds read past end of line while indenting C code

CVE-2014-0160

Chain: "Heartbleed" bug receives an inconsistent length parameter (CWE-130) enabling an out-of-bounds read (CWE-126), returning memory that could include private cryptographic keys and other sensitive data.

CVE-2009-2523

Chain: product does not handle when an input string is not NULL terminated, leading to buffer over-read or heap-based buffer overflow.

Detection Methods

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

Vulnerability Mapping Notes

Justification : This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : 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.

NotesNotes

These problems may be resultant from missing sentinel values (CWE-463) or trusting a user-influenced input length variable.
A buffer over-read typically occurs when the pointer or its index is incremented to a position past the end of the buffer or when pointer arithmetic results in a position after the valid memory location.

References

REF-1034

Breaking the memory secrecy assumption
Raoul Strackx, Yves Younan, Pieter Philippaerts, Frank Piessens, Sven Lachmund, Thomas Walter.
https://dl.acm.org/doi/10.1145/1519144.1519145

REF-1035

The info leak era on software exploitation
Fermin J. Serna.
https://media.blackhat.com/bh-us-12/Briefings/Serna/BH_US_12_Serna_Leak_Era_Slides.pdf

REF-44

24 Deadly Sins of Software Security
Michael Howard, David LeBlanc, John Viega.

Submission

Name Organization Date Date release Version
PLOVER 2006-07-19 +00:00 2006-07-19 +00:00 Draft 3

Modifications

Name Organization Date Comment
CWE Content Team MITRE 2008-09-08 +00:00 updated Applicable_Platforms, Relationships, Taxonomy_Mappings, Weakness_Ordinalities
CWE Content Team MITRE 2009-10-29 +00:00 updated Description, Relationship_Notes, Relationships
CWE Content Team MITRE 2011-03-29 +00:00 updated Demonstrative_Examples
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2012-05-11 +00:00 updated Demonstrative_Examples, Relationships
CWE Content Team MITRE 2014-06-23 +00:00 updated Observed_Examples
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2017-11-08 +00:00 updated Causal_Nature, Demonstrative_Examples
CWE Content Team MITRE 2018-03-27 +00:00 updated Demonstrative_Examples
CWE Content Team MITRE 2019-09-19 +00:00 updated Common_Consequences, References
CWE Content Team MITRE 2020-02-24 +00:00 updated Relationships
CWE Content Team MITRE 2020-06-25 +00:00 updated Demonstrative_Examples
CWE Content Team MITRE 2023-01-31 +00:00 updated Description
CWE Content Team MITRE 2023-04-27 +00:00 updated Detection_Factors, References, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2023-10-26 +00:00 updated Observed_Examples
CWE Content Team MITRE 2025-04-03 +00:00 updated Common_Consequences, Description, Diagram, Other_Notes
The information presented on CVE Find originates from several carefully selected reference sources. CVE data is provided by MITRE Corporation and the National Vulnerability Database (NVD). The Known Exploited Vulnerabilities (KEV) catalog is sourced from the Cybersecurity and Infrastructure Security Agency (CISA), while EPSS scores come from FIRST.org. Additionally, data regarding software weaknesses (CWE) and common attack patterns (CAPEC) is maintained by MITRE Corporation, and information on hardware and software configurations (CPE) is provided by the NVD.