Bug 2541253 (CVE-2026-97950)

Summary: CVE-2026-97950 kernel: configfs: pin the symlink target's dirent instead of chasing ->ci_dentry
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's configfs filesystem. A local user could exploit a race condition between creating a symbolic link and deleting its target directory to cause a Denial of Service (DoS). When this race condition occurs, the kernel attempts to access a freed directory entry, which can lead to an inconsistent state or a system crash.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-25 11:11:11 UTC 
In the Linux kernel, the following vulnerability has been resolved:

configfs: pin the symlink target's dirent instead of chasing ->ci_dentry

create_link() reads the target's configfs_dirent from
item->ci_dentry->d_fsdata, relying on the item reference taken by
get_target().  That reference pins the item, not its dentry: the dentry is
pinned by DCACHE_PERSISTENT, which configfs_remove_dir() releases via
simple_rmdir() while the item is still alive.  A symlink racing with rmdir
of its target can therefore find ->ci_dentry freed and its dirent
released, triggering WARN_ON(!atomic_read(&sd->s_count)) in configfs_get().

Take the dirent in get_target() as well, under ->d_lock and atomically
with the item reference, and pass it down to create_link().  A hashed
dentry has not been killed yet, so its ->d_fsdata reference keeps the
dirent alive there.
Comment 1 Keith Grant 2026-09-29 22:35:39 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97950.mbox