CVE-2022-49290 mac80211: fix potential double free on mesh join
A double free vulnerability in the Linux kernel mac80211 mesh module allows attackers to cause a kernel panic or potentially execute code via specific mesh join sequences.
- 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-2022-49290?
CVE-2022-49290 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:
mac80211: fix potential double free on mesh join
While commit 6a01afcf8468 ("mac80211: mesh: Free ie data when leaving mesh") fixed a memory leak on mesh leave / teardown it introduced a potential memory corruption caused by a double free when rejoining the mesh:
ieee80211_leave_mesh() -> kfree(sdata->u.mesh.ie); ... ieee80211_join_mesh() -> copy_mesh_setup() -> old_ie = ifmsh->ie; -> kfree(old_ie);
This double free / kernel panics can be reproduced by using wpa_supplicant with an encrypted mesh (if set up without encryption via "iw" then ifmsh->ie is always NULL, which avoids this issue). And then calling:
$ iw dev mesh0 mesh leave $ iw dev mesh0 mesh join my-mesh
Note that typically these commands are not used / working when using wpa_supplicant. And it seems that wpa_supplicant or wpa_cli are going through a NETDEV_DOWN/NETDEV_UP cycle between a mesh leave and mesh join where the NETDEV_UP resets the mesh.ie to NULL via a memcpy of default_mesh_setup in cfg80211_netdev_notifier_call, which then avoids the memory corruption, too.
The issue was first observed in an application which was not using wpa_supplicant but "Senf" instead, which implements its own calls to nl80211.
Fixing the issue by removing the kfree()'ing of the mesh IE in the mesh join function and leaving it solely up to the mesh leave to free the mesh IE.
Weakness: CWE-415
Which versions are affected by CVE-2022-49290?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49290?
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-2022-49290 being exploited?
There is no known exploitation of CVE-2022-49290 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49290, GHSA-9368-p9r2-276c, UBUNTU-CVE-2022-49290.