CWE-127

Buffer Under-read. [Improper-Control-Of-A-Resource-Through-Its-Lifetime]

Required inputs: IR, StaticSemanticAnalysis

The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations prior to the targeted buffer. This typically occurs when the pointer or its index is decremented to a position before the buffer, when pointer arithmetic results in a position before the beginning of the valid memory location, or when a negative index is used. This may result in exposure of sensitive information or possibly a crash.Excerpts from CWE [https://cwe.mitre.org], Copyright (C) 2006-2026, the MITRE Corporation. See section 9.4. "3rd-Party Licenses" in the documentation for full details.

Possible Messages

Key	Text	Severity	Disabled
arithmetic_out_of_bounds	Pointer arithmetic on {node0} might create pointer outside array bounds of {name0}	None	False
out_of_bounds	Access into array is out of bounds	None	False
possible_indirect_out_of_bounds	Pointer-indirect access through {node0} might be out of bounds accessing {name0}	None	False
possible_out_of_bounds	Access into array might be out of bounds	None	False
undereferenced_arithmetic_out_of_bounds	Pointer arithmetic on {node0} might create pointer one past the end of {name0} (but not dereferenced)	None	False
undereferenced_out_of_bounds	Access is one past the end of the array (but not dereferenced)	None	False
undereferenced_possible_indirect_out_of_bounds	Pointer-indirect access through {node0} might be one past the end accessing {name0} (but not dereferenced)	None	False
undereferenced_possible_out_of_bounds	Access might be one past the end of the array (but not dereferenced)	None	False

Options

• This rule shares the following common options: exclude_in_macros, exclude_messages_in_system_headers, excludes, extend_exclude_to_macro_invocations, includes, justification_checker, languages, post_processing, provider, report_at, severity

• The following places define options that affect this rule: Stylechecks, Analysis-GlobalOptions

abstract_interpretation_out_of_bounds

abstract_interpretation_out_of_bounds : bool = False

Use additional "symbolic expression analysis" as postprocessing step. This can remove false positives, but might require more time. Option is automatically active if option StaticSemanticAnalysis/performance.general.enhanced_analysis is active.

 

exclude_very_high_indices

exclude_very_high_indices : bool = True

Enables heuristic to detect false positives: When index used for array access is very high in comparison to the array's size, assume false positive.

 

report_unbounded_arrays

report_unbounded_arrays : bool = False

If true, accesses into arrays with unknown bound are reported as being potentially outside the allowed range. This affects arrays like extern char buf[];.

 

report_undereferenced_one_past_the_end

report_undereferenced_one_past_the_end : bool = False

If true, report accesses one past the end of an array even if there is no dereference of the resulting pointer.

 

report_unknown_index

report_unknown_index : bool = False

If false, do not report possible out-of-bound findings for which the analysis was not able to infer any restricting information about the array index (this can lead to excluding both false positives and true findings).