# CVE-2025-38492: netfs: Fix race between cache write completion and ALL_QUEUED being set > A race condition in the Linux kernel netfs subsystem can cause asynchronous cache write requests to hang, leading to a denial of service. - **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 28 Jul 2025 - **Updated:** 11 May 2026 - **Also known as:** BELL-CVE-2025-38492, GHSA-4x9f-4x9p-28w2, UBUNTU-CVE-2025-38492 ## What is CVE-2025-38492? CVE-2025-38492 is a medium-severity vulnerability in Linux kernel, published on 28 Jul 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 race between cache write completion and ALL_QUEUED being set When netfslib is issuing subrequests, the subrequests start processing immediately and may complete before we reach the end of the issuing function. At the end of the issuing function we set NETFS_RREQ_ALL_QUEUED to indicate to the collector that we aren't going to issue any more subreqs and that it can do the final notifications and cleanup. Now, this isn't a problem if the request is synchronous (NETFS_RREQ_OFFLOAD_COLLECTION is unset) as the result collection will be done in-thread and we're guaranteed an opportunity to run the collector. However, if the request is asynchronous, collection is primarily triggered by the termination of subrequests queuing it on a workqueue. Now, a race can occur here if the app thread sets ALL_QUEUED after the last subrequest terminates. This can happen most easily with the copy2cache code (as used by Ceph) where, in the collection routine of a read request, an asynchronous write request is spawned to copy data to the cache. Folios are added to the write request as they're unlocked, but there may be a delay before ALL_QUEUED is set as the write subrequests may complete before we get there. If all the write subreqs have finished by the ALL_QUEUED point, no further events happen and the collection never happens, leaving the request hanging. Fix this by queuing the collector after setting ALL_QUEUED. This is a bit heavy-handed and it may be sufficient to do it only if there are no extant subreqs. Also add a tracepoint to cross-reference both requests in a copy-to-request operation and add a trace to the netfs_rreq tracepoint to indicate the setting of ALL_QUEUED. Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization) ## Which versions are affected by CVE-2025-38492? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2025-38492? Apply the vendor's patch. ## Is CVE-2025-38492 being exploited? There is no known exploitation of CVE-2025-38492 in the wild and no public exploit code. ## Other vulnerabilities in Linux kernel - [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild) - [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild) - [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild) - [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild) - [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2025-38492 and fix it if it is affected. What it is: CVE-2025-38492 is a medium-severity vulnerability in Linux kernel, published on 28 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2025-38492 in the wild and no public exploit code. Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2025-38492/ (Markdown: https://insights.sbomify.com/CVE-2025-38492/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38492 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38492 - OSV: https://osv.dev/vulnerability/CVE-2025-38492 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-38492/ Summaries are generated and may contain mistakes; the official description above is the record.