CVE-2023-4194 Kernel: tap: tap_open(): correctly initialize socket uid next fix of i_uid to current_fsuid
A local attacker can bypass network filters and gain unauthorized resource access due to incorrect socket UID initialization in the Linux kernel TUN/TAP driver.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-4194?
CVE-2023-4194 is a medium-severity authentication bypass vulnerability in Debian Debian Linux, published on 7 Aug 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A flaw was found in the Linux kernel's TUN/TAP functionality. This issue could allow a local user to bypass network filters and gain unauthorized access to some resources. The original patches fixing CVE-2023-1076 are incorrect or incomplete. The problem is that the following upstream commits - a096ccca6e50 ("tun: tun_chr_open(): correctly initialize socket uid"), - 66b2c338adce ("tap: tap_open(): correctly initialize socket uid"), pass "inode->i_uid" to sock_init_data_uid() as the last parameter and that turns out to not be accurate.
Which versions are affected by CVE-2023-4194?
It affects 4 products.
Products include Debian Debian Linux, Fedoraproject Fedora, Linux kernel, Redhat Enterprise Linux.
How do I fix CVE-2023-4194?
Apply the vendor's patch.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2023-4194 being exploited?
There is no known exploitation of CVE-2023-4194 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-27890, DEBIAN-CVE-2023-4194, GHSA-9cmp-2g73-ff98, UBUNTU-CVE-2023-4194.