CVE-2023-1386: Qemu: 9pfs: suid/sgid bits not dropped on file write
A flaw was discovered in 9pfs. Jietao Xiao and his team found that when a local user in the guest tries to write an executable file with SUID or SGID, none of these privileged bits are correctly dropped. As a result, in rare circumstances(exist an executable file owned by root, writable by others, has SUID/SGID bits), this flaw could be used by malicious users in the guest to elevate their privileges within the guest and help a host's local user to elevate privileges on the host.
Upstream issue: https://github.com/v9fs/linux/issues/29
Other sources
A flaw was found in the 9p passthrough filesystem (9pfs) implementation in QEMU. When a local user in the guest writes an executable file with SUID or SGID, none of these privileged bits are correctly dropped. As a result, in rare circumstances, this flaw could be used by malicious users in the guest to elevate their privileges within the guest and help a host local user to elevate privileges on the host.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the vulnerability ID for this flaw?
The vulnerability ID for this flaw is CVE-2023-1386.
What is the severity level of CVE-2023-1386?
CVE-2023-1386 has a severity level of 7.8 (high).
What is the affected software for CVE-2023-1386?
The affected software for CVE-2023-1386 is QEMU and Fedora 38.
How can this vulnerability be exploited?
This vulnerability can be exploited by a local user in the guest writing an executable file with SUID or SGID.
Are there any fixes available for CVE-2023-1386?
Yes, fixes are available. Please refer to the provided references for more information.