CVE-2026-89636 smb: client: clear ce->tgthint in free_tgts()
A use-after-free vulnerability in the Linux kernel SMB client allows attackers to potentially execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89636?
CVE-2026-89636 is a critical use after free vulnerability in Linux, published on 11 Sep 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:
smb: client: clear ce->tgthint in free_tgts()
When free_tgts() frees all structures in ce->tlist, ce->tgthint is left pointing to one of the freed cache_dfs_tgt structures.
If ce->tgthint is not reset before it is used later, it results in a use-after-free.
Set ce->tgthint to NULL in free_tgts() after the elements are freed to reflect that no elements remain.
Which versions are affected by CVE-2026-89636?
How do I fix CVE-2026-89636?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-89636 being exploited?
There is no known exploitation of CVE-2026-89636 in the wild and no public exploit code.
Sources
Also known as AZL-100472, BELL-CVE-2026-89636, DEBIAN-CVE-2026-89636, GHSA-4452-h45j-w5mp, UBUNTU-CVE-2026-89636.