CVE-2024-35811 wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach
A use-after-free vulnerability in the Linux kernel's brcmfmac Wi-Fi driver allows attackers to cause denial of service or execute code via USB hotplug events.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-35811?
CVE-2024-35811 is a high-severity use after free vulnerability in Debian Debian Linux, published on 17 May 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:
wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach
This is the candidate patch of CVE-2023-47233 : https://nvd.nist.gov/vuln/detail/CVE-2023-47233
In brcm80211 driver,it starts with the following invoking chain to start init a timeout worker:
->brcmf_usb_probe ->brcmf_usb_probe_cb ->brcmf_attach ->brcmf_bus_started ->brcmf_cfg80211_attach ->wl_init_priv ->brcmf_init_escan ->INIT_WORK(&cfg->escan_timeout_work, brcmf_cfg80211_escan_timeout_worker);
If we disconnect the USB by hotplug, it will call brcmf_usb_disconnect to make cleanup. The invoking chain is :
brcmf_usb_disconnect ->brcmf_usb_disconnect_cb ->brcmf_detach ->brcmf_cfg80211_detach ->kfree(cfg);
While the timeout woker may still be running. This will cause a use-after-free bug on cfg in brcmf_cfg80211_escan_timeout_worker.
Fix it by deleting the timer and canceling the worker in brcmf_cfg80211_detach.
[[email protected]: keep timer delete as is and cancel work just before free]
Weakness: CWE-416
Which versions are affected by CVE-2024-35811?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2024-35811?
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-2024-35811 being exploited?
There is no known exploitation of CVE-2024-35811 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2024-35811, DEBIAN-CVE-2024-35811, GHSA-m253-3j38-482h, UBUNTU-CVE-2024-35811.