The vulnerability arises when the ext4 filesystem frees its superblock information (sbi) and associated counters before a grace period following the last reference to a mount. During an active pathwalk in ext4_get_link, the kernel may dereference a NULL s_fs_info, a freed sbi, or destroyed counters, leading to a KASAN reported null pointer dereference. This results in a kernel panic, effectively creating a denial‑of‑service condition for the affected machine. The flaw is triggered by a race between an ext4 get_link operation and the unmount process.

All Linux kernel releases that include the ext4 filesystem are potentially affected. The vulnerability was discovered in the kernel source and does not refer to specific vendor distribution versions. Thus any distribution that ships the standard Linux kernel and uses ext4 for its filesystems may be impacted until a patch is released.

The EPSS score is not available and the issue is not listed in the CISA KEV catalog, indicating low public exploitation intelligence. The description notes that the race is hard to trigger, and no public exploit has been documented. The CVSS score is not reported, but based on the impact of a kernel crash, the severity could be high if a successful exploit is achieved. Attackers would need to orchestrate a timing attack that unmounts while a directory walk is ongoing, which is non‑trivial and likely requires local or privilege escalation.