CWE-226 (在释放前未清除敏感信息) — Vulnerability Class 35

35 vulnerabilities classified as CWE-226 (在释放前未清除敏感信息). AI Chinese analysis included.

CWE-226 represents a resource management weakness where sensitive data remains in memory or files after they are released for reuse. This flaw typically allows attackers to exploit residual information by accessing the recycled resource before it is overwritten, thereby retrieving confidential credentials, encryption keys, or personal data that should have been discarded. Developers can prevent this vulnerability by implementing rigorous zeroization procedures, ensuring that all sensitive contents are explicitly cleared or overwritten with neutral values immediately before releasing the resource. Additionally, adopting secure coding standards that mandate automatic cleanup during object destruction or using memory-safe languages can significantly reduce the risk of accidental data leakage, ensuring that critical state transitions do not expose previously held information to unauthorized entities.

MITRE CWE Description

The product releases a resource such as memory or a file so that it can be made available for reuse, but it does not clear or "zeroize" the information contained in the resource before the product performs a critical state transition or makes the resource available for reuse by other entities. When resources are released, they can be made available for reuse. For example, after memory is de-allocated, an operating system may make the memory available to another process, or disk space may be reallocated when a file is deleted. As removing information requires time and additional resources, operating systems do not usually clear the previously written information. Even when the resource is reused by the same process, this weakness can arise when new data is not as large as the old data, which leaves portions of the old data still available. Equivalent errors can occur in other situations where the length of data is variable but the associated data structure is not. If memory is not cleared after use, the information may be read by less trustworthy parties when the memory is reallocated. This weakness can apply in hardware, such as when a device or system switches between power, sleep, or debug states during normal operation, or when execution changes to different users or privilege levels.

Common Consequences (1)

Confidentiality Read Application Data

Mitigations (2)

Architecture and Design, Implementation During critical state transitions, information not needed in the next state should be removed or overwritten with fixed patterns (such as all 0's) or random data, before the transition to the next state.

Effectiveness: High

Architecture and Design, Implementation When releasing, de-allocating, or deleting a resource, overwrite its data and relevant metadata with fixed patterns or random data. Be cautious about complex resource types whose underlying representation might be non-contiguous or change at a low level, such as how a file might be split into different chunks on a file system, even though "logical" file positions are contiguous at the application …

Effectiveness: High

Examples (2)

This example shows how an attacker can take advantage of an incorrect state transition.

During the transition from A to B, the device does not scrub the memory.

Bad · Other

For transition from state A to state B, remove information which should not be available once the transition is complete.

Good · Other

The following code calls realloc() on a buffer containing sensitive data:

cleartext_buffer = get_secret();... cleartext_buffer = realloc(cleartext_buffer, 1024); ... scrub_memory(cleartext_buffer, 1024);

Bad · C

CVE ID	Title	CVSS	Severity	Published
CVE-2023-1637	Linux kernel 安全漏洞 — Kernel	7.1	-	2023-03-27
CVE-2022-39393	Wasmtime vulnerable to data leakage between instances in the pooling allocator — wasmtime	8.6	High	2022-11-10
CVE-2020-27218	Eclipse Jetty 安全漏洞 — Eclipse Jetty	4.8	-	2020-11-28
CVE-2019-1573	Information Disclosure in GlobalProtect Agent — GlobalProtect Agent	2.5	Low	2019-04-09
CVE-2018-7166	Joyent Node.js 缓冲区错误漏洞 — Node.js	7.5	-	2018-08-21

Vulnerabilities classified as CWE-226 (在释放前未清除敏感信息) represent 35 CVEs. The CWE taxonomy describes the weakness; review individual CVEs for product-specific impact.