CVE-2023-53606

CVE-2023-53606 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: clean up potential nfsd_file refcount leaks in COPY codepath There are two different flavors of the nfsd4_copy struct. One is embedded in the compound and is used directly in synchronous copies. The other is dynamically allocated, refcounted and tracked in the client struture. For the embedded one, the cleanup just involves releasing any nfsd_files held on its behalf. For the async one, the cleanup is a bit more involved, and we need to dequeue it from lists, unhash it, etc. There is at least one potential refcount leak in this code now. If the kthread_create call fails, then both the src and dst nfsd_files in the original nfsd4_copy object are leaked. The cleanup in this codepath is also sort of weird. In the async copy case, we'll have up to four nfsd_file references (src and dst for both flavors of copy structure). They are both put at the end of nfsd4_do_async_copy, even though the ones held on behalf of the embedded one outlive that structure. Change it so that we always clean up the nfsd_file refs held by the embedded copy structure before nfsd4_copy returns. Rework cleanup_async_copy to handle both inter and intra copies. Eliminate nfsd4_cleanup_intra_ssc since it now becomes a no-op.

Frequently asked questions

What is CVE-2023-53606?
In the Linux kernel, the following vulnerability has been resolved: nfsd: clean up potential nfsd_file refcount leaks in COPY codepath There are two different flavors of the nfsd4_copy struct. One is embedded in the compound and is used directly in synchronous copies. The other is dynamically allocated, refcounted and tracked in the client struture. For the embedded one, the cleanup just involves releasing any nfsd_files held on its behalf. For the async one, the cleanup is a bit more involved, and we need to dequeue it from lists, unhash it, etc. There is at least one potential refcount leak in this code now. If the kthread_create call fails, then both the src and dst nfsd_files in the original nfsd4_copy object are leaked. The cleanup in this codepath is also sort of weird. In the async copy case, we'll have up to four nfsd_file references (src and dst for both flavors of copy structure). They are both put at the end of nfsd4_do_async_copy, even though the ones held on behalf of the embedded one outlive that structure. Change it so that we always clean up the nfsd_file refs held by the embedded copy structure before nfsd4_copy returns. Rework cleanup_async_copy to handle both inter and intra copies. Eliminate nfsd4_cleanup_intra_ssc since it now becomes a no-op.
How severe is CVE-2023-53606?
CVE-2023-53606 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-53606 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-53606?
CVE-2023-53606 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-53606?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-53606 have an EU (EUVD) identifier?
Yes. CVE-2023-53606 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-32260.
When was CVE-2023-53606 published?
CVE-2023-53606 was published on 2025-10-04 and last updated on 2026-06-17.

References

Affected products (1)

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