CVE-2024-26878 quota: Fix potential NULL pointer dereference
A race condition in the Linux kernel quota subsystem can lead to a NULL pointer dereference, causing a system crash.
- 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-2024-26878?
CVE-2024-26878 is a medium-severity vulnerability in Debian Debian Linux, published on 17 Apr 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:
quota: Fix potential NULL pointer dereference
Below race may cause NULL pointer dereference
P1 P2 dquot_free_inode quota_off drop_dquot_ref remove_dquot_ref dquots = i_dquot(inode) dquots = i_dquot(inode) srcu_read_lock dquots[cnt]) != NULL (1) dquots[type] = NULL (2) spin_lock(&dquots[cnt]->dq_dqb_lock) (3) ....
If dquot_free_inode(or other routines) checks inode's quota pointers (1) before quota_off sets it to NULL(2) and use it (3) after that, NULL pointer dereference will be triggered.
So let's fix it by using a temporary pointer to avoid this issue.
Which versions are affected by CVE-2024-26878?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2024-26878?
Apply the vendor's patch.
Is CVE-2024-26878 being exploited?
There is no known exploitation of CVE-2024-26878 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2024-26878, DEBIAN-CVE-2024-26878, GHSA-jg7c-h6xh-f8hr, UBUNTU-CVE-2024-26878.