Strix
26.1K

CVE-2021-47334

HIGHCVSS 7.8/10EPSS 0.28%

Last modified

CVE-2021-47334 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: misc/libmasm/module: Fix two use after free in ibmasm_init_one In ibmasm_init_one, it calls ibmasm_init_remote_input_dev(). Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are allocated by input_allocate_device(), and assigned to sp->remote.mouse_dev and sp->remote.keybd_dev respectively. In the err_free_devices error branch of ibmasm_init_one, mouse_dev and keybd_dev are freed by input_free_device(), and return error. Then the execution runs into error_send_message error branch of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev. My patch add a "error_init_remote" label to handle the error of ibmasm_init_remote_input_dev(), to avoid the uaf bugs.. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: misc/libmasm/module: Fix two use after free in ibmasm_init_one In ibmasm_init_one, it calls ibmasm_init_remote_input_dev(). Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are allocated by input_allocate_device(), and assigned to sp->remote.mouse_dev and sp->remote.keybd_dev respectively. In the err_free_devices error branch of ibmasm_init_one, mouse_dev and keybd_dev are freed by input_free_device(), and return error. Then the execution runs into error_send_message error branch of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev. My patch add a "error_init_remote" label to handle the error of ibmasm_init_remote_input_dev(), to avoid the uaf bugs.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.28%

19.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel< 4.4.276
LinuxLinux Kernel>= 4.5, < 4.9.276
LinuxLinux Kernel>= 4.10, < 4.14.240
LinuxLinux Kernel>= 4.15, < 4.19.198
LinuxLinux Kernel>= 4.20, < 5.4.134
LinuxLinux Kernel>= 5.5, < 5.10.52
LinuxLinux Kernel>= 5.11, < 5.12.19
LinuxLinux Kernel>= 5.13, < 5.13.4

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2021-47334?
In the Linux kernel, the following vulnerability has been resolved: misc/libmasm/module: Fix two use after free in ibmasm_init_one In ibmasm_init_one, it calls ibmasm_init_remote_input_dev(). Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are allocated by input_allocate_device(), and assigned to sp->remote.mouse_dev and sp->remote.keybd_dev respectively. In the err_free_devices error branch of ibmasm_init_one, mouse_dev and keybd_dev are freed by input_free_device(), and return error. Then the execution runs into error_send_message error branch of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev. My patch add a "error_init_remote" label to handle the error of ibmasm_init_remote_input_dev(), to avoid the uaf bugs.
How severe is CVE-2021-47334?
CVE-2021-47334 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.
How do I fix CVE-2021-47334?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-47334?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST