CVE-2020-36694: linux linux_kernel Use After Free

Vulnerability summary

CVE-2020-36694 is a medium (CVSS 6.7) Use After Free vulnerability in linux linux_kernel. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 38.6% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 21-05-2023
   PublishedVulnerability first disclosed.
2. 31-01-2025
   Last modifiedVulnerability information updated.

Description

An issue was discovered in netfilter in the Linux kernel before 5.10. There can be a use-after-free in the packet processing context, because the per-CPU sequence count is mishandled during concurrent iptables rules replacement. This could be exploited with the CAP_NET_ADMIN capability in an unprivileged namespace. NOTE: cc00bca was reverted in 5.12.

• 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.