CVE-2026-53026

CVE-2026-53026 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. 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: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg In nfsd4_add_rdaccess_to_wrdeleg, if fp->fi_fds[O_RDONLY] is already set by another thread, __nfs4_file_get_access should not be called to increment the nfs4_file access count since that was already done by the thread that added READ access to the file. The extra fi_access count in nfs4_file can prevent the corresponding nfsd_file from being freed. When stopping nfs-server service, these extra access counts trigger a BUG in kmem_cache_destroy() that shows nfsd_file object remaining on __kmem_cache_shutdown. This problem can be reproduced by running the Git project's test suite over NFS.

Frequently asked questions

What is CVE-2026-53026?
In the Linux kernel, the following vulnerability has been resolved: NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg In nfsd4_add_rdaccess_to_wrdeleg, if fp->fi_fds[O_RDONLY] is already set by another thread, __nfs4_file_get_access should not be called to increment the nfs4_file access count since that was already done by the thread that added READ access to the file. The extra fi_access count in nfs4_file can prevent the corresponding nfsd_file from being freed. When stopping nfs-server service, these extra access counts trigger a BUG in kmem_cache_destroy() that shows nfsd_file object remaining on __kmem_cache_shutdown. This problem can be reproduced by running the Git project's test suite over NFS.
How severe is CVE-2026-53026?
CVE-2026-53026 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-53026 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-53026?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-53026 have an EU (EUVD) identifier?
Yes. CVE-2026-53026 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38894.
When was CVE-2026-53026 published?
CVE-2026-53026 was published on 2026-06-24 and last updated on 2026-06-28.

References