CVE-2021-20226: linux linux_kernel Use After Free

Vulnerability summary

CVE-2021-20226 is a high (CVSS 7.8) Use After Free vulnerability in linux linux_kernel. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 36.5% of scored vulnerabilities.

Timeline

1. 23-02-2021
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

Description

A use-after-free flaw was found in the io_uring in Linux kernel, where a local attacker with a user privilege could cause a denial of service problem on the system The issue results from the lack of validating the existence of an object prior to performing operations on the object by not incrementing the file reference counter while in use. The highest threat from this vulnerability is to data integrity, confidentiality and system availability.

• CWE-416Use After FreeThe 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.