CVE-2023-32249 ksmbd: not allow guest user on multichannel
An attacker can bypass authentication restrictions by using guest sessions in multichannel SMB connections, potentially gaining unauthorized access.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-32249?
CVE-2023-32249 is a critical authentication bypass vulnerability in Linux kernel, published on 16 Aug 2025. 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:
ksmbd: not allow guest user on multichannel
This patch return STATUS_NOT_SUPPORTED if binding session is guest.
Which versions are affected by CVE-2023-32249?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-32249?
Apply the vendor's patch.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2023-32249 being exploited?
There is no known exploitation of CVE-2023-32249 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-32249, DEBIAN-CVE-2023-32249, GHSA-xv7h-524v-h227, ROOT-OS-DEBIAN-11-CVE-2023-32249, UBUNTU-CVE-2023-32249.