Use-after-free in Linux kernel - CVE-2020-36385
Published: November 23, 2021 / Updated: December 6, 2021
Vulnerability identifier: #VU58332
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2020-36385
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a use-after-free error in drivers/infiniband/core/ucma.c, because the ctx is reached via the ctx_list in some ucma_migrate_id situations where ucma_close is called. A local user can run a specially crafted program to trigger the use-after-free error and execute arbitrary code with elevated privileges.
How to mitigate CVE-2020-36385
Install updates from vendor's website.
Sources
- https://syzkaller.appspot.com/bug?id=457491c4672d7b52c1007db213d93e47c711fae6
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f5449e74802c1112dea984aec8af7a33c4516af1
- https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-ucma_close-2
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10