Bug 2532527 (CVE-2026-89668) - CVE-2026-89668 kernel: Linux Kernel: nfsd use-after-free due to incorrect debugfs initialization order
Summary: CVE-2026-89668 kernel: Linux Kernel: nfsd use-after-free due to incorrect deb...
Keywords:
Status: NEW
Alias: CVE-2026-89668
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-11 23:41 UTC by OSIDB Bzimport
Modified: 2026-09-12 00:02 UTC (History)
15 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-11 23:41:07 UTC
In the Linux kernel, the following vulnerability has been resolved:

nfsd: move nfsd_debugfs_init() after nfsd4_init_slabs() in init_nfsd()

nfsd_debugfs_init() runs before nfsd4_init_slabs() in init_nfsd().
If the slab allocation fails, the bare "return retval" bypasses
nfsd_debugfs_exit(), leaving orphan debugfs files with stale fops
pointers into the freed module text.

Move nfsd_debugfs_init() to after the slab init succeeds, so the
early return has no debugfs state to clean up.

Since debugfs is now the more recently initialized of the two, also
update the unwind paths to match reverse-initialization (LIFO) order:
run nfsd_debugfs_exit() before nfsd4_free_slabs() in both the
init_nfsd() error path and exit_nfsd(). The nfsd debugfs files only
reference module-global state and have no dependency on the slab
caches, so that reordering is a cleanup with no functional change.


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