{"@ID": "825", "@Name": "Expired Pointer Dereference", "@Abstraction": "Base", "@Structure": "Simple", "@Status": "Incomplete", "Description": "The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.", "Extended_Description": "When a product releases memory, but it maintains a pointer to that memory, then the memory might be re-allocated at a later time. If the original pointer is accessed to read or write data, then this could cause the product to read or modify data that is in use by a different function or process. Depending on how the newly-allocated memory is used, this could lead to a denial of service, information exposure, or code execution.", "Related_Weaknesses": {"Related_Weakness": [{"@Nature": "ChildOf", "@CWE_ID": "119", "@View_ID": "1000", "@Ordinal": "Primary"}, {"@Nature": "ChildOf", "@CWE_ID": "119", "@View_ID": "1305", "@Ordinal": "Primary"}, {"@Nature": "ChildOf", "@CWE_ID": "119", "@View_ID": "1340", "@Ordinal": "Primary"}, {"@Nature": "ChildOf", "@CWE_ID": "672", "@View_ID": "1000"}, {"@Nature": "CanPrecede", "@CWE_ID": "125", "@View_ID": "1000"}, {"@Nature": "CanPrecede", "@CWE_ID": "787", "@View_ID": "1000"}]}, "Weakness_Ordinalities": {"Weakness_Ordinality": {"Ordinality": "Resultant"}}, "Applicable_Platforms": {"Language": [{"@Class": "Memory-Unsafe", "@Prevalence": "Undetermined"}, {"@Name": "C", "@Prevalence": "Undetermined"}, {"@Name": "C++", "@Prevalence": "Undetermined"}]}, "Alternate_Terms": {"Alternate_Term": {"Term": "Dangling pointer"}}, "Modes_Of_Introduction": {"Introduction": {"Phase": "Implementation"}}, "Common_Consequences": {"Consequence": [{"Scope": "Confidentiality", "Impact": "Read Memory", "Note": "If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application."}, {"Scope": "Availability", "Impact": "DoS: Crash, Exit, or Restart", "Note": "If the expired pointer references a memory location that is not accessible to the product, or points to a location that is \"malformed\" (such as NULL) or larger than expected by a read or write operation, then a crash may occur."}, {"Scope": ["Integrity", "Confidentiality", "Availability"], "Impact": "Execute Unauthorized Code or Commands", "Note": "If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible."}]}, "Detection_Methods": {"Detection_Method": [{"@Detection_Method_ID": "DM-14", "Method": "Automated Static Analysis", "Description": "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.)"}, {"@Detection_Method_ID": "DM-15", "Method": "Automated Dynamic Analysis", "Description": "Use tools that are integrated during\n\t     compilation to insert runtime error-checking mechanisms\n\t     related to memory safety errors, such as AddressSanitizer\n\t     (ASan) for C/C++ [REF-1518].", "Effectiveness": "Moderate", "Effectiveness_Notes": "Crafted inputs are necessary to\n\t     reach the code containing the error, such as generated\n\t     by fuzzers.  Also, these tools may reduce performance,\n\t     and they only report the error condition - not the\n\t     original mistake that led to the\n\t     error."}]}, "Potential_Mitigations": {"Mitigation": [{"Phase": "Architecture and Design", "Description": "Choose a language that provides automatic memory management."}, {"Phase": "Implementation", "Description": "When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy."}]}, "Demonstrative_Examples": {"Demonstrative_Example": [{"@Demonstrative_Example_ID": "DX-71", "Intro_Text": "The following code shows a simple example of a use after free error:", "Example_Code": {"@Nature": "Bad", "@Language": "C", "xhtml:div": {"xhtml:br": [null, null, null], "xhtml:div": [{"@style": "margin-left:1em;", "xhtml:br": null, "#text": "abrt = 1;free(ptr);"}, {"@style": "margin-left:1em;", "#text": "logError(\"operation aborted before commit\", ptr);"}], "#text": "char* ptr = (char*)malloc (SIZE);if (err) {}...if (abrt) {}"}}, "Body_Text": "When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function."}, {"@Demonstrative_Example_ID": "DX-72", "Intro_Text": "The following code shows a simple example of a double free error:", "Example_Code": {"@Nature": "Bad", "@Language": "C", "xhtml:div": {"xhtml:br": [null, null, null, null], "xhtml:div": {"@style": "margin-left:1em;", "#text": "free(ptr);"}, "#text": "char* ptr = (char*)malloc (SIZE);...if (abrt) {}...free(ptr);"}}, "Body_Text": ["Double free vulnerabilities have two common (and sometimes overlapping) causes:", {"xhtml:ul": {"xhtml:li": [{"xhtml:div": "Error conditions and other exceptional circumstances"}, {"xhtml:div": "Confusion over which part of the program is responsible for freeing the memory"}]}}, "Although some double free vulnerabilities are not much more complicated than the previous example, most are spread out across hundreds of lines of code or even different files. Programmers seem particularly susceptible to freeing global variables more than once."]}]}, "Observed_Examples": {"Observed_Example": [{"Reference": "CVE-2023-26463", "Description": "Chain: IPSec VPN product uses the same variable for multiple purposes in the same function (CWE-1109), leading to incorrect access control (CWE-284) and expired pointer dereference (CWE-825)", "Link": "https://www.cve.org/CVERecord?id=CVE-2023-26463"}, {"Reference": "CVE-2008-5013", "Description": "access of expired memory address leads to arbitrary code execution", "Link": "https://www.cve.org/CVERecord?id=CVE-2008-5013"}, {"Reference": "CVE-2010-3257", "Description": "stale pointer issue leads to denial of service and possibly other consequences", "Link": "https://www.cve.org/CVERecord?id=CVE-2010-3257"}, {"Reference": "CVE-2008-0062", "Description": "Chain: a message having an unknown message type may cause a reference to uninitialized memory resulting in a null pointer dereference (CWE-476) or dangling pointer (CWE-825), possibly crashing the system or causing heap corruption.", "Link": "https://www.cve.org/CVERecord?id=CVE-2008-0062"}, {"Reference": "CVE-2007-1211", "Description": "read of value at an offset into a structure after the offset is no longer valid", "Link": "https://www.cve.org/CVERecord?id=CVE-2007-1211"}]}, "Functional_Areas": {"Functional_Area": "Memory Management"}, "Affected_Resources": {"Affected_Resource": "Memory"}, "References": {"Reference": {"@External_Reference_ID": "REF-1518"}}, "Mapping_Notes": {"Usage": "Allowed", "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.", "Reasons": {"Reason": {"@Type": "Acceptable-Use"}}}, "Notes": {"Note": [{"@Type": "Maintenance", "#text": "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."}, {"@Type": "Terminology", "#text": "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."}]}, "Content_History": {"Submission": {"Submission_Name": "CWE Content Team", "Submission_Organization": "MITRE", "Submission_Date": "2010-09-22", "Submission_Version": "1.10", "Submission_ReleaseDate": "2010-09-27"}, "Modification": [{"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2011-06-27", "Modification_Version": "2.0", "Modification_ReleaseDate": "2011-06-27", "Modification_Comment": "updated Demonstrative_Examples, Potential_Mitigations, Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2012-05-11", "Modification_Version": "2.2", "Modification_ReleaseDate": "2012-05-15", "Modification_Comment": "updated Demonstrative_Examples, Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2013-02-21", "Modification_Version": "2.4", "Modification_ReleaseDate": "2013-02-21", "Modification_Comment": "updated Alternate_Terms"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2020-02-24", "Modification_Version": "4.0", "Modification_ReleaseDate": "2020-02-24", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2020-08-20", "Modification_Version": "4.2", "Modification_ReleaseDate": "2020-08-20", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2020-12-10", "Modification_Version": "4.3", "Modification_ReleaseDate": "2020-12-10", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2021-03-15", "Modification_Version": "4.4", "Modification_ReleaseDate": "2021-03-15", "Modification_Comment": "updated Observed_Examples"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2022-04-28", "Modification_Version": "4.7", "Modification_ReleaseDate": "2022-04-28", "Modification_Comment": "updated Research_Gaps"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2023-01-31", "Modification_Version": "4.10", "Modification_ReleaseDate": "2023-01-31", "Modification_Comment": "updated Common_Consequences, Description"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2023-04-27", "Modification_Version": "4.11", "Modification_ReleaseDate": "2023-04-27", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2023-06-29", "Modification_Version": "4.12", "Modification_ReleaseDate": "2023-06-29", "Modification_Comment": "updated Mapping_Notes"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2025-04-03", "Modification_Version": "4.17", "Modification_ReleaseDate": "2025-04-03", "Modification_Comment": "updated Applicable_Platforms"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2025-09-09", "Modification_Version": "4.18", "Modification_ReleaseDate": "2025-09-09", "Modification_Comment": "updated Affected_Resources, Functional_Areas"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2025-12-11", "Modification_Version": "4.19", "Modification_ReleaseDate": "2025-12-11", "Modification_Comment": "updated Applicable_Platforms, Detection_Factors, Observed_Examples, References, Time_of_Introduction, Weakness_Ordinalities"}]}}