CVE-2022-49622 netfilter: nf_tables: avoid skb access on nf_stolen
A use-after-free vulnerability in the Linux kernel netfilter subsystem allows attackers to cause denial of service or execute code when tracing is enabled.
- 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-2022-49622?
CVE-2022-49622 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 2025. 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:
netfilter: nf_tables: avoid skb access on nf_stolen
When verdict is NF_STOLEN, the skb might have been freed.
When tracing is enabled, this can result in a use-after-free: 1. access to skb->nf_trace 2. access to skb->mark 3. computation of trace id 4. dump of packet payload
To avoid 1, keep a cached copy of skb->nf_trace in the trace state struct. Refresh this copy whenever verdict is != STOLEN.
Avoid 2 by skipping skb->mark access if verdict is STOLEN.
3 is avoided by precomputing the trace id.
Only dump the packet when verdict is not "STOLEN".
Weakness: CWE-416
Which versions are affected by CVE-2022-49622?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49622?
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-2022-49622 being exploited?
There is no known exploitation of CVE-2022-49622 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-59013, DEBIAN-CVE-2022-49622, GHSA-xf4c-frc6-wrrh, ROOT-OS-DEBIAN-11-CVE-2022-49622, ROOT-OS-UBUNTU-2204-CVE-2022-49622, UBUNTU-CVE-2022-49622.