CVE-2022-49393 misc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl
A logic error in the Linux kernel's fastrpc driver causes a kernel crash when unmapping memory, leading to denial of service.
- 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-2022-49393?
CVE-2022-49393 is a high-severity 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:
misc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl
This is another instance of incorrect use of list iterator and checking it for NULL.
The list iterator value 'map' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty (in this case, the check 'if (!map) {' will always be false and never exit as expected).
To fix the bug, use a new variable 'iter' as the list iterator, while use the original variable 'map' as a dedicated pointer to point to the found element.
Without this patch, Kernel crashes with below trace:
Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000ffff7fb03750 ... Call trace: fastrpc_map_create+0x70/0x290 [fastrpc] fastrpc_req_mem_map+0xf0/0x2dc [fastrpc] fastrpc_device_ioctl+0x138/0xc60 [fastrpc] __arm64_sys_ioctl+0xa8/0xec invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0xd4/0xfc do_el0_svc+0x28/0x90 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xa4/0x130 el0t_64_sync+0x18c/0x190 Code: 14000016 f94000a5 eb05029f 54000260 (b94018a6) ---[ end trace 0000000000000000 ]---
Weakness: CWE-670
Which versions are affected by CVE-2022-49393?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49393?
Apply the vendor's patch.
Is CVE-2022-49393 being exploited?
There is no known exploitation of CVE-2022-49393 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49393, GHSA-jh22-4f6v-h4ph, ROOT-OS-UBUNTU-2204-CVE-2022-49393, UBUNTU-CVE-2022-49393.