CVE-2024-49855 nbd: fix race between timeout and normal completion
A race condition in the Linux kernel NBD driver can lead to a use-after-free, potentially allowing local attackers to 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-2024-49855?
CVE-2024-49855 is a critical use after free vulnerability in Linux kernel, published on 21 Oct 2024. 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:
nbd: fix race between timeout and normal completion
If request timetout is handled by nbd_requeue_cmd(), normal completion has to be stopped for avoiding to complete this requeued request, other use-after-free can be triggered.
Fix the race by clearing NBD_CMD_INFLIGHT in nbd_requeue_cmd(), meantime make sure that cmd->lock is grabbed for clearing the flag and the requeue.
Weakness: CWE-416
Which versions are affected by CVE-2024-49855?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-49855?
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-2024-49855 being exploited?
There is no known exploitation of CVE-2024-49855 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-50640, BELL-CVE-2024-49855, DEBIAN-CVE-2024-49855, GHSA-x6h6-973g-q656, ROOT-OS-UBUNTU-2204-CVE-2024-49855, UBUNTU-CVE-2024-49855.