Chi tiết CWE-761

CWE-761

Free of Pointer not at Start of Buffer
2009-05-27
00h00 +00:00
Incomplete
2026-10-28
00h00 +00:00
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Quản lý thông báo

Tên: Free of Pointer not at Start of Buffer

The product calls free() on a pointer to a memory resource that was allocated on the heap, but the pointer is not at the start of the buffer.

Thông tin chung

Các cách xuất hiện

Implementation : This weakness often occurs when the memory is allocated explicitly on the heap with one of the malloc() family functions and free() is called, but pointer arithmetic has caused the pointer to be in the interior or end of the buffer.

Nền tảng áp dụng

Ngôn ngữ

Lớp: Memory-Unsafe (Often)
Tên: C (Undetermined)

Hậu quả phổ biến

Phạm vi Tác động Khả năng xảy ra
Integrity
Availability
Confidentiality
Modify Memory, DoS: Crash, Exit, or Restart, Execute Unauthorized Code or Commands

Ghi chú: This can cause the product to crash, or in some cases, modify critical program variables or execute code.

Ví dụ đã quan sát

Tài liệu tham khảo Mô tả

CVE-2019-11930

function "internally calls 'calloc' and returns a pointer at an index... inside the allocated buffer. This led to freeing invalid memory."

Các biện pháp giảm thiểu tiềm năng

Phases : Implementation
When utilizing pointer arithmetic to traverse a buffer, use a separate variable to track progress through memory and preserve the originally allocated address for later freeing.
Phases : Implementation
When programming in C++, consider using smart pointers provided by the boost library to help correctly and consistently manage memory.
Phases : Architecture and Design
Phases : Architecture and Design
Use a language that provides abstractions for memory allocation and deallocation.

Phương pháp phát hiện

Automated Dynamic Analysis

Use tools that are integrated during compilation to insert runtime error-checking mechanisms related to memory safety errors, such as AddressSanitizer (ASan) for C/C++ [REF-1518] or valgrind [REF-480].
Hiệu quả : Moderate

Ghi chú ánh xạ lỗ hổng

Lý do : 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.
Bình luận : 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.

Ghi chú

Currently, CWE-763 is the parent, however it may be desirable to have an intermediate parent which is not function-specific, similar to how CWE-762 is an intermediate parent between CWE-763 and CWE-590.

Tài liệu tham khảo

REF-657

boost C++ Library Smart Pointers
https://www.boost.org/doc/libs/1_38_0/libs/smart_ptr/smart_ptr.htm

REF-480

Valgrind
https://valgrind.org/

REF-1518

AddressSanitizer
https://clang.llvm.org/docs/AddressSanitizer.html

Gửi

Tên Tổ chức Ngày Ngày phát hành Version
CWE Content Team MITRE 2009-05-08 +00:00 2009-05-27 +00:00 1.4

Sửa đổi

Tên Tổ chức Ngày Bình luận
CWE Content Team MITRE 2010-09-27 +00:00 updated Relationships
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 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2014-02-18 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2020-02-24 +00:00 updated Relationships
CWE Content Team MITRE 2020-12-10 +00:00 updated Relationships
CWE Content Team MITRE 2021-03-15 +00:00 updated Observed_Examples
CWE Content Team MITRE 2023-01-31 +00:00 updated Description
CWE Content Team MITRE 2023-04-27 +00:00 updated References, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2025-09-09 +00:00 updated Functional_Areas, References
CWE Content Team MITRE 2025-12-11 +00:00 updated Applicable_Platforms, Detection_Factors, Potential_Mitigations, References, Weakness_Ordinalities
CWE Content Team MITRE 2026-04-30 +00:00 updated Detection_Factors
CWE Content Team MITRE 2026-10-28 +00:00 updated Common_Consequences, Demonstrative_Examples, Description, Modes_of_Introduction