CVE-2026-68312 cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths
A memory leak in the Linux kernel CIFS module can lead to resource exhaustion and denial of service under memory pressure.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68312?
CVE-2026-68312 is a denial of service vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths
In cifs_close_deferred_file(), cifs_close_all_deferred_files(), and cifs_close_deferred_file_under_dentry(), when a pending deferred close is cancelled via cancel_delayed_work(), the subsequent kmalloc_obj() to add the file to the local processing list may fail under memory pressure. The loop breaks immediately, but the cancelled work is no longer pending (it would have called _cifsFileInfo_put()), and the cfile is never added to file_head for processing. The cifsFileInfo reference and the open server handle both leak.
Fix by saving the cfile that failed allocation in a local variable, breaking as before, and calling _cifsFileInfo_put() on it after releasing the lock. Any files later in the iteration are unaffected since their deferred work is still pending and will fire normally.
Which versions are affected by CVE-2026-68312?
How do I fix CVE-2026-68312?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-68312 being exploited?
There is no known exploitation of CVE-2026-68312 in the wild and no public exploit code.
Sources
Also known as AZL-94953, BELL-CVE-2026-68312, DEBIAN-CVE-2026-68312, GHSA-cm4r-jfcj-c3ff, UBUNTU-CVE-2026-68312.