cve/2021/CVE-2021-3492.md

### [CVE-2021-3492](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3492)
![](https://img.shields.io/static/v1?label=Product&message=Linux%20kernel&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=5.8%20kernel%3C%205.8.0-50.56%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-401%3A%20Missing%20Release%20of%20Memory%20after%20Effective%20Lifetime&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-415%3A%20Double%20Free&color=brighgreen)

### Description

Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.

### POC

#### Reference
- http://packetstormsecurity.com/files/162614/Kernel-Live-Patch-Security-Notice-LSN-0077-1.html

#### Github
- https://github.com/ARPSyndicate/cvemon
- https://github.com/NaInSec/CVE-PoC-in-GitHub
- https://github.com/SYRTI/POC_to_review
- https://github.com/WhooAmii/POC_to_review
- https://github.com/hac425xxx/heap-exploitation-in-real-world
- https://github.com/joydo/CVE-Writeups
- https://github.com/k0mi-tg/CVE-POC
- https://github.com/kdn111/linux-kernel-exploitation
- https://github.com/khanhdn111/linux-kernel-exploitation
- https://github.com/khanhdz-06/linux-kernel-exploitation
- https://github.com/khanhdz191/linux-kernel-exploitation
- https://github.com/khanhhdz/linux-kernel-exploitation
- https://github.com/khanhhdz06/linux-kernel-exploitation
- https://github.com/khanhnd123/linux-kernel-exploitation
- https://github.com/knd06/linux-kernel-exploitation
- https://github.com/manas3c/CVE-POC
- https://github.com/ndk06/linux-kernel-exploitation
- https://github.com/ndk191/linux-kernel-exploitation
- https://github.com/nomi-sec/PoC-in-GitHub
- https://github.com/soosmile/POC
- https://github.com/ssr-111/linux-kernel-exploitation
- https://github.com/synacktiv/CVE-2021-3492
- https://github.com/trhacknon/Pocingit
- https://github.com/whoforget/CVE-POC
- https://github.com/wkhnh06/linux-kernel-exploitation
- https://github.com/xairy/linux-kernel-exploitation
- https://github.com/youwizard/CVE-POC
- https://github.com/zecool/cve