CWE-252 (未加检查的返回值) — Vulnerability Class 76

76 vulnerabilities classified as CWE-252 (未加检查的返回值). AI Chinese analysis included.

CWE-252 represents a critical programming weakness where software fails to verify the return value of a function or method, often stemming from the erroneous assumption that operations cannot fail or that their failure is inconsequential. This oversight allows attackers to exploit the vulnerability by forcing functions to return unexpected error codes or null values, thereby disrupting the intended execution flow. When the program proceeds without validating these outcomes, it may operate in an unstable state, leading to data corruption, denial of service, or privilege escalation. To mitigate this risk, developers must rigorously implement error-handling routines that explicitly check return statuses. By treating every function call as potentially hazardous and ensuring subsequent logic accounts for failure conditions, programmers can prevent attackers from manipulating program state through unchecked return values.

MITRE CWE Description

The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions. Two common programmer assumptions are "this function call can never fail" and "it doesn't matter if this function call fails". If an attacker can force the function to fail or otherwise return a value that is not expected, then the subsequent program logic could lead to a vulnerability, because the product is not in a state that the programmer assumes. For example, if the program calls a function to drop privileges but does not check the return code to ensure that privileges were successfully dropped, then the program will continue to operate with the higher privileges.

Common Consequences (1)

Availability, Integrity Unexpected State, DoS: Crash, Exit, or Restart

An unexpected return value could place the system in a state that could lead to a crash or other unintended behaviors.

Mitigations (4)

Implementation Check the results of all functions that return a value and verify that the value is expected.

Effectiveness: High

Implementation For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished [REF-1484].

Implementation Ensure that you account for all possible return values from the function.

Implementation When designing a function, make sure you return a value or throw an exception in case of an error.

Examples (2)

Consider the following code segment:

char buf[10], cp_buf[10]; fgets(buf, 10, stdin); strcpy(cp_buf, buf);

Bad · C

In the following example, it is possible to request that memcpy move a much larger segment of memory than assumed:

int returnChunkSize(void *) { /* if chunk info is valid, return the size of usable memory, * else, return -1 to indicate an error */ ... } int main() { ... memcpy(destBuf, srcBuf, (returnChunkSize(destBuf)-1)); ... }

Bad · C

CVE ID	Title	CVSS	Severity	Published
CVE-2022-43763	Lack of checking preconditions in APROL — B&R APROL	7.5	High	2023-02-08
CVE-2022-3108	Linux kernel 安全漏洞 — Kernel	5.5	-	2022-12-14
CVE-2022-23476	Unchecked return value from xmlTextReaderExpand in Nokogiri — nokogiri	7.5	High	2022-12-08
CVE-2022-31225	Dell BIOS 安全漏洞 — CPG BIOS	3.0	Low	2022-09-12
CVE-2022-1319	Red Hat Undertow 安全漏洞 — undertow	7.5	-	2022-08-31
CVE-2022-0485	libnbd 代码问题漏洞 — libnbd	6.5	-	2022-08-29
CVE-2021-3659	Linux kernel 代码问题漏洞 — Kernel	5.5	-	2022-08-22
CVE-2021-41041	Eclipse OpenJ9 安全漏洞 — Eclipse OpenJ9	5.3	-	2022-04-27
CVE-2021-42780	OpenSC 安全漏洞 — opensc	5.3	-	2022-04-18
CVE-2021-40401	Gerbv 资源管理错误漏洞 — Gerbv	8.8	-	2022-02-04
CVE-2021-34585	CODESYS V2 web server: crafted requests could trigger a pointer dereference with an invalid address (DoS) — CODESYS V2	7.5	High	2021-10-26
CVE-2021-31366	Junos OS: MX Series: In subscriber management / BBE configuration authd can crash if a subscriber with a specific username tries to login leading to a DoS — Junos OS	6.5	Medium	2021-10-19
CVE-2021-37625	Incorrect Check of Function Return Value in Skytable — skytable	7.5	High	2021-08-05
CVE-2020-17533	Apache Accumulo Improper Handling of Insufficient Permissions — Apache Accumulo	8.1	-	2020-12-29
CVE-2020-6152	Accusoft ImageGear 缓冲区错误漏洞 — Accusoft	8.8	-	2020-09-01
CVE-2018-14622	libtirpc 安全漏洞 — libtirpc	7.5	-	2018-08-30

Vulnerabilities classified as CWE-252 (未加检查的返回值) represent 76 CVEs. The CWE taxonomy describes the weakness; review individual CVEs for product-specific impact.