A flaw in the F2FS filesystem of the Linux kernel causes the free sections counter to be overestimated when a segment range is freed. The logic that should reduce the counter by the number of already‑free sections in the truncated range fails, leading the kernel to believe more space is available than actually is. If storage is tight, this can force the garbage collector to fail or trigger assertion errors, potentially causing the file system to become unavailable. The weakness is an improper initialization or bookkeeping error (CWE‑665).

The issue is present in the Linux kernel implementation of the F2FS filesystem. It applies to all distributions that ship the affected kernel version and use F2FS as a storage backend. No specific kernel release numbers are listed in the data; kernel maintainers should check that the latest stable release contains the patch that corrects the free_sections accounting logic.

The CVSS score is not provided, but the lack of an EPSS score and the absence of a KEV listing suggest that, so far, there is no publicly known exploitation. The flaw is local in nature and requires the ability to manipulate file‑system metadata (for example, by writing to a file that triggers a free_segment_range). An attacker with local or privileged access could use the overflow in the free counter to force allocation failures or crash the file system, leading to denial of service for applications that rely on the affected storage. As the vulnerability is not listed in CISA’s KEV catalog and no exploit probability is reported, the likelihood of immediate exploitation is low, yet the impact warrants prompt remediation.