CVE-2024-57941 netfs: Fix the (non-)cancellation of copy when cache is temporarily disabled

What is CVE-2024-57941?

CVE-2024-57941 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

netfs: Fix the (non-)cancellation of copy when cache is temporarily disabled

When the caching for a cookie is temporarily disabled (e.g. due to a DIO write on that file), future copying to the cache for that file is disabled until all fds open on that file are closed. However, if netfslib is using the deprecated PG_private_2 method (such as is currently used by ceph), and decides it wants to copy to the cache, netfs_advance_write() will just bail at the first check seeing that the cache stream is unavailable, and indicate that it dealt with all the content.

This means that we have no subrequests to provide notifications to drive the state machine or even to pin the request and the request just gets discarded, leaving the folios with PG_private_2 set.

Fix this by jumping directly to cancel the request if the cache is not available. That way, we don't remove mark3 from the folio_queue list and netfs_pgpriv2_cancel() will clean up the folios.

This was found by running the generic/013 xfstest against ceph with an active cache and the "-o fsc" option passed to ceph. That would usually hang

Which versions are affected by CVE-2024-57941?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-57941?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2024-57941 being exploited?

There is no known exploitation of CVE-2024-57941 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2024-57941, DEBIAN-CVE-2024-57941, GHSA-vfxx-4xcx-mgvh, UBUNTU-CVE-2024-57941.