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CWE-416 (释放后使用) — Vulnerability Class 2490

2490 vulnerabilities classified as CWE-416 (释放后使用). AI Chinese analysis included.

CWE-416, Use After Free, is a critical memory safety weakness occurring when a program continues to reference a memory location after it has been deallocated. Attackers typically exploit this vulnerability by freeing an object and then rapidly reallocating that same memory block with attacker-controlled data. Because the original pointer still points to the now-invalid address, the application may inadvertently execute malicious code or corrupt memory structures, often leading to arbitrary code execution or denial of service. To prevent this, developers must rigorously manage memory lifecycles by nullifying pointers immediately after freeing them, ensuring no dangling references remain. Utilizing modern programming languages with automatic garbage collection or employing static analysis tools to detect invalid memory accesses further mitigates the risk, ensuring that freed memory is never accessed again during the program’s execution.

MITRE CWE Description
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Common Consequences (4)
IntegrityModify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
AvailabilityDoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
ConfidentialityRead Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity, Confidentiality, AvailabilityExecute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap …
Mitigations (2)
Architecture and DesignChoose a language that provides automatic memory management.
ImplementationWhen 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.
Effectiveness: Defense in Depth
Examples (2)
The following example demonstrates the weakness.
#include <stdio.h> #include <unistd.h> #define BUFSIZER1 512 #define BUFSIZER2 ((BUFSIZER1/2) - 8) int main(int argc, char **argv) { char *buf1R1; char *buf2R1; char *buf2R2; char *buf3R2; buf1R1 = (char *) malloc(BUFSIZER1); buf2R1 = (char *) malloc(BUFSIZER1); free(buf2R1); buf2R2 = (char *) malloc(BUFSIZER2); buf3R2 = (char *) malloc(BUFSIZER2); strncpy(buf2R1, argv[1], BUFSIZER1-1); free(buf1R1); free(buf2R2); free(buf3R2); }
Bad · C
The following code illustrates a use after free error:
char* ptr = (char*)malloc (SIZE); if (err) { abrt = 1; free(ptr); } ... if (abrt) { logError("operation aborted before commit", ptr); }
Bad · C
CVE IDTitleCVSSSeverityPublished
CVE-2021-39836 Adobe Acrobat Reader DC AcroForm buttonGetIcon Use-After-Free Remote Code Execution Vulnerability — Acrobat Reader 7.8 -2021-09-29
CVE-2021-41539 Siemens Solid Edge 资源管理错误漏洞 — Solid Edge SE2021 7.8 -2021-09-28
CVE-2021-41540 Siemens Solid Edge 资源管理错误漏洞 — Solid Edge SE2021 7.8 -2021-09-28
CVE-2021-41537 Siemens Solid Edge 资源管理错误漏洞 — Solid Edge SE2021 7.8 -2021-09-28
CVE-2021-41536 Siemens Solid Edge 资源管理错误漏洞 — Solid Edge SE2021 7.8 -2021-09-28
CVE-2021-41535 Siemens Solid Edge 资源管理错误漏洞 — NX 1953 Series 7.8 -2021-09-28
CVE-2021-39216 Use after free passing `externref`s to Wasm in Wasmtime — wasmtime 6.3 Medium2021-09-17
CVE-2021-39228 Memory Safety Issue when using patch or merge on state and assign the result back to state — tremor-runtime 6.5 Medium2021-09-17
CVE-2021-3796 Use After Free in vim/vim — vim/vim 7.8 -2021-09-15
CVE-2021-37202 Siemens NX 资源管理错误漏洞 — NX 1980 Series 7.8 -2021-09-14
CVE-2021-28553 Adobe Acrobat Reader use-after-free vulnerability could lead to arbitrary code execution — Acrobat Reader 8.8 -2021-09-02
CVE-2021-28550 Adobe Acrobat Reader use after free vulnerability could lead to arbitrary code execution — Acrobat Reader 8.8 -2021-09-02
CVE-2021-36055 XMP Toolkit SDK Use After Free Vulnerability In ReadingXMPNewDOM Could Lead To Arbitrary Code Execution — XMP Toolkit 7.8 High2021-09-01
CVE-2021-32781 Continued processing of requests after locally generated response — envoy 8.6 High2021-08-24
CVE-2021-28631 Adobe Acrobat Reader DC AcroForm Field Use-After-Free Remote Code Execution Vulnerability — Acrobat Reader 7.8 High2021-08-24
CVE-2021-28552 Adobe Acrobat Reader DC XFA Template Use-After-Free Remote Code Execution Vulnerability — Acrobat Reader 7.8 High2021-08-24
CVE-2021-28632 ZDI-CAN-13471: Adobe Acrobat Reader DC AcroForm Field Use-After-Free Remote Code Execution Vulnerability — Acrobat Reader 7.8 High2021-08-24
CVE-2021-36008 Adobe Illustrator PDF File Parsing Use-After-Free Information Disclosure Vulnerability — Illustrator 3.3 Low2021-08-20
CVE-2021-35981 Adobe Acrobat Reader DC launchURL Use-After-Free Remote Code Execution Vulnerability — Acrobat Reader 7.8 High2021-08-20
CVE-2021-35983 Adobe Acrobat Reader DC AcroForm Use-After-Free Remote Code Execution Vulnerability — Acrobat Reader 7.8 High2021-08-20
CVE-2021-28640 Adobe Acrobat Reader Use-After-Free Arbitrary Code Execution Vulnerability — Acrobat Reader 7.3 High2021-08-20
CVE-2021-28641 Adobe Acrobat Reader Use-After-Free Arbitrary Code Execution Vulnerability — Acrobat Reader 7.8 High2021-08-20
CVE-2021-28639 Adobe Acrobat Reader DC setAction Use-After-Free Remote Code Execution Vulnerability — Acrobat Reader 7.8 High2021-08-20
CVE-2021-28635 Adobe Acrobat Reader Use-After-Free Vulnerability — Acrobat Reader 7.8 High2021-08-20
CVE-2021-28593 Adobe Illustrator PostScript Parsing Use-After-Free Information Disclosure Vulnerability — Illustrator 3.3 Low2021-08-20
CVE-2020-28594 PrusaSlicer 资源管理错误漏洞 — Prusa Research 7.8 -2021-08-17
CVE-2021-22940 node core 资源管理错误漏洞 — Node 7.5 -2021-08-16
CVE-2021-37690 Use after free and segfault in shape inference functions in TensorFlow — tensorflow 6.6 Medium2021-08-12
CVE-2021-37652 Use after free in boosted trees creation in TensorFlow — tensorflow 7.8 High2021-08-12
CVE-2021-37179 Siemens Solid Edge 资源管理错误漏洞 — Solid Edge SE2021 7.8 -2021-08-10

Vulnerabilities classified as CWE-416 (释放后使用) represent 2490 CVEs. The CWE taxonomy describes the weakness; review individual CVEs for product-specific impact.