CVE-2023-3609: Use-after-free in Linux kernel's net/sched: cls_u32 component

Vulnerability summary

CVE-2023-3609 is a high (CVSS 7.8) Use After Free vulnerability in debian debian_linux. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 41.9% of scored vulnerabilities.

Timeline

1. 21-07-2023
   PublishedVulnerability first disclosed.
2. 14-10-2026
   Last modifiedVulnerability information updated.

Description

A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation. If tcf_change_indev() fails, u32_set_parms() will immediately return an error after incrementing or decrementing the reference counter in tcf_bind_filter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability. We recommend upgrading past commit 04c55383fa5689357bcdd2c8036725a55ed632bc.

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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.