CVE-2024-44947 fuse: Initialize beyond-EOF page contents before setting uptodate
Local attackers can read uninitialized kernel memory via mmap on systems without init-on-alloc enabled, leaking sensitive data.
- 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-2024-44947?
CVE-2024-44947 is a medium-severity vulnerability in Linux kernel, published on 2 Sep 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:
fuse: Initialize beyond-EOF page contents before setting uptodate
fuse_notify_store(), unlike fuse_do_readpage(), does not enable page zeroing (because it can be used to change partial page contents).
So fuse_notify_store() must be more careful to fully initialize page contents (including parts of the page that are beyond end-of-file) before marking the page uptodate.
The current code can leave beyond-EOF page contents uninitialized, which makes these uninitialized page contents visible to userspace via mmap().
This is an information leak, but only affects systems which do not enable init-on-alloc (via CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y or the corresponding kernel command line parameter).
Weakness: CWE-665
Which versions are affected by CVE-2024-44947?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-44947?
Apply the vendor's patch.
Is CVE-2024-44947 being exploited?
There is no known exploitation of CVE-2024-44947 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-49296, AZL-49307, BELL-CVE-2024-44947, DEBIAN-CVE-2024-44947, GHSA-xjwh-3rm6-w25h, UBUNTU-CVE-2024-44947.