Use-after-free in Linux kernel - CVE-2021-3640
Published: May 27, 2022
Vulnerability identifier: #VU63769
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-3640
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 sco_sock_sendmsg() function of the Linux kernel HCI subsystem. A privileged local user can call ioct UFFDIO_REGISTER or other way trigger race condition to escalate privileges on the system.
How to mitigate CVE-2021-3640
Install updates from vendor's website.
Sources
- https://github.com/torvalds/linux/commit/99c23da0eed4fd20cae8243f2b51e10e66aa0951
- https://bugzilla.redhat.com/show_bug.cgi?id=1980646
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/bluetooth/sco.c?h=v5.16&id=99c23da0eed4fd20cae8243f2b51e10e66aa0951
- https://www.openwall.com/lists/oss-security/2021/07/22/1
- https://ubuntu.com/security/CVE-2021-3640
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
- https://www.debian.org/security/2022/dsa-5096
- https://security.netapp.com/advisory/ntap-20220419-0003/