CVE-2026-43215 cifs: Fix locking usage for tcon fields
A race condition in the Linux kernel CIFS module due to incorrect locking can lead to system instability or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-43215?
CVE-2026-43215 is a high-severity vulnerability in Linux kernel, published on 6 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
cifs: Fix locking usage for tcon fields
We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization.
There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock.
Which versions are affected by CVE-2026-43215?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43215?
Apply the vendor's patch.
Is CVE-2026-43215 being exploited?
There is no known exploitation of CVE-2026-43215 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43215, DEBIAN-CVE-2026-43215, GHSA-qhpw-2qgq-68px, ROOT-OS-DEBIAN-11-CVE-2026-43215, ROOT-OS-DEBIAN-12-CVE-2026-43215, ROOT-OS-UBUNTU-2204-CVE-2026-43215 and 2 more.