CVE-2026-53026

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxc07dc84ed67c5a182273171639bacbbb87c12175 < 4584229395d0d65bd517780afe97ffea07cb2c3daffected
LinuxLinux8072e34e1387d03102b788677d491e2bcceef6f5 < b81572b073441dfd32213e41857676d0dbff4665affected
LinuxLinux8072e34e1387d03102b788677d491e2bcceef6f5 < b48f44f36e6607b2f818560f19deb86b4a9c717baffected
LinuxLinux6.18.4 < 6.18.33affected
LinuxLinux6.19affected
LinuxLinux0 < 6.19unaffected
LinuxLinux6.18.33 <= 6.18.*unaffected
LinuxLinux7.0.10 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References