CVE-2021-46952 NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds
A local attacker can cause a denial of service in the Linux kernel by providing an invalid UDP retransmission value during NFS mount.
- 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-2021-46952?
CVE-2021-46952 is a high-severity vulnerability in Linux kernel, published on 27 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds
Fix shift out-of-bounds in xprt_calc_majortimeo(). This is caused by a garbage timeout (retrans) mount option being passed to nfs mount, in this case from syzkaller.
If the protocol is XPRT_TRANSPORT_UDP, then 'retrans' is a shift value for a 64-bit long integer, so 'retrans' cannot be >= 64. If it is >= 64, fail the mount and return an error.
Weakness: CWE-125
Which versions are affected by CVE-2021-46952?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-46952?
Apply the vendor's patch.
Is CVE-2021-46952 being exploited?
There is no known exploitation of CVE-2021-46952 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-46952, GHSA-jrxj-mm3c-m6gg, UBUNTU-CVE-2021-46952.