CVE-2026-64031

Status: UPDATED  |  Advisory ID: CVE-2026-64031

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

erofs: fix managed cache race for unaligned extents

After unaligned compressed extents were introduced, the following race

could occur:

[Thread 1] [Thread 2]

(z_erofs_fill_bio_vec)

<handle a Z_EROFS_PREALLOCATED_FOLIO folio>

...

filemap_add_folio (1)

(z_erofs_bind_cache)

<the same folio is found..>

..

..

folio_attach_private (2)

filemap_add_folio (3) again

Since (1) is executed but (2) hasn't been executed yet, it's possible

that another thread finds the same managed folio in z_erofs_bind_cache()

for a different pcluster and calls filemap_add_folio() again since

folio->private is still Z_EROFS_PREALLOCATED_FOLIO.

Fix this by explicitly clearing folio->private before making the folio

visible in the managed cache so that another pcluster can simply wait

on the locked managed folio as what we did for other shared cases [1].

This only impacts unaligned data compression (`-E48bit` with zstd,

for example).

[1] Commit 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of

crafted images properly") was originally introduced to handle crafted

overlapped extents, but it addresses unaligned extents as well. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References