SB20260727364 - Use-after-free in Linux kernel netfs_unlock_abandoned_read_pages() and netfs_unlock_read_folio()

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-64216)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in netfs_unlock_abandoned_read_pages() and netfs_unlock_read_folio() when handling abandoned read pages and read folios. A local user can trigger the vulnerable code path to cause a denial of service.

The issue occurs because ownership of the folio specified by no_unlock_folio reverts to the caller after NETFS_RREQ_IN_PROGRESS is cleared, making dereference of that folio unsafe in this context.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/3866d015f33aeedf81338dd99154703bef33faef
• https://git.kernel.org/stable/c/6080fa3ecfbb4448a3b47368629534c09b6ec750
• https://git.kernel.org/stable/c/dbe556972100fabb8e5a1b3d2163831ff07b1e8e