CVE-2024-26739 net/sched: act_mirred: don't override retval if we already lost the skb
A use-after-free vulnerability in the Linux kernel's act_mirred scheduler allows attackers to cause denial of service or potentially execute code.
- 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-2024-26739?
CVE-2024-26739 is a high-severity use after free vulnerability in Debian Debian Linux, published on 3 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:
net/sched: act_mirred: don't override retval if we already lost the skb
If we're redirecting the skb, and haven't called tcf_mirred_forward(), yet, we need to tell the core to drop the skb by setting the retcode to SHOT. If we have called tcf_mirred_forward(), however, the skb is out of our hands and returning SHOT will lead to UaF.
Move the retval override to the error path which actually need it.
Weakness: CWE-416
Which versions are affected by CVE-2024-26739?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2024-26739?
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-2024-26739 being exploited?
There is no known exploitation of CVE-2024-26739 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-54954, BELL-CVE-2024-26739, DEBIAN-CVE-2024-26739, GHSA-rwch-8cp4-7v7r, ROOT-OS-DEBIAN-11-CVE-2024-26739, ROOT-OS-DEBIAN-12-CVE-2024-26739 and 2 more.