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CVE Record

CVE-2025-38534: netfs: Fix copy-to-cache so that it performs collection with ceph+fscache

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix copy-to-cache so that it performs collection with ceph+fscache The netfs copy-to-cache that is used by Ceph with local caching sets up a new request to write data just read to the cache. The request is started and then left to look after itself whilst the app continues. The request gets notified by the backing fs upon completion of the async DIO write, but then tries to wake up the app because NETFS_RREQ_OFFLOAD_COLLECTION isn't set - but the app isn't waiting there, and so the request just hangs. Fix this by setting NETFS_RREQ_OFFLOAD_COLLECTION which causes the notification from the backing filesystem to put the collection onto a work queue instead.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can make Ceph local cache copy-back work hang after data is read. The described impact is operational reliability, not confirmed data theft or remote compromise. Evidence is narrow: Ceph with fscache/local caching is the named scenario, and severity details are not provided.

Executive priority

Treat as targeted operational risk. Prioritize review for production Ceph environments using local caching, especially where hangs could affect service availability. Broader emergency response is not supported by the provided evidence.

Technical view

The netfs copy-to-cache path used by Ceph with local caching creates an asynchronous write request to cache recently read data. Because NETFS_RREQ_OFFLOAD_COLLECTION was not set, completion handling tried to wake an application that was not waiting, leaving the request hung. The fix routes collection to a work queue.

Likely exposure

Exposure appears limited to Linux systems using Ceph with fscache/local caching on kernel versions identified by the CVE source bundle. The bundle names Linux kernel 6.14, 6.15.8, and 6.16 data, but does not provide a plain affected-range explanation.

Exploitation context

The source bundle does not cite active exploitation, public exploit activity, or KEV listing. The described failure is a kernel request hang in a specific Ceph local-caching code path, so assess it as a reliability risk unless vendor advisories state broader impact.

Researcher notes

The record lacks CVSS, CWE, and explicit affected-range detail. The clearest technical signal is the netfs/Ceph fscache async completion hang and the fix setting NETFS_RREQ_OFFLOAD_COLLECTION to offload collection handling.

Mitigation direction

  • Check Linux distribution and kernel vendor advisories for CVE-2025-38534 applicability.
  • Update to a kernel build containing the referenced stable fixes.
  • Prioritize systems using Ceph with fscache or local caching enabled.
  • If patching is delayed, ask the vendor for supported operational mitigations.

Validation and detection

  • Inventory Linux kernel versions across Ceph clients and storage nodes.
  • Identify hosts using Ceph with fscache or local caching enabled.
  • Confirm whether installed kernels include the referenced stable commits.
  • Monitor affected systems for cache write hangs or related kernel warnings.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2025-38534 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
3Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe2d46f2ec332533816417b60933954173f602121, e2d46f2ec332533816417b60933954173f602121unaffected
LinuxLinux6.14, 0, 6.15.8, 6.16affected
Weakness

CWE details

No CWE listed

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