CVE-2016-6198: Medium severity linux kernel vulnerability
It was found that the vfsrename() function did not detect hard links on overlayfs. A local, unprivileged user could use the rename syscall on overlayfs on top of xfs to crash the system.
Upstream patches:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=54d5ca871e72f2bb172ec9323497f01cd5091ec7 https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9409e22acdfc9153f88d9b1ed2bd2a5b34d2d3ca
CVE assignment:
http://seclists.org/oss-sec/2016/q3/42
Other sources
The filesystem layer in the Linux kernel before 4.5.5 proceeds with post-rename operations after an OverlayFS file is renamed to a self-hardlink, which allows local users to cause a denial of service (system crash) via a rename system call, related to fs/namei.c and fs/open.c.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2016-6198?
CVE-2016-6198 is considered critical as it allows local unprivileged users to crash the system.
How does CVE-2016-6198 impact overlayfs?
CVE-2016-6198 allows the vfs_rename() function to fail to detect hard links on overlayfs, leading to potential system crashes.
How do I fix CVE-2016-6198?
To fix CVE-2016-6198, update the Linux kernel to versions 4.5.5 or newer, or apply the relevant patches.
Which systems are affected by CVE-2016-6198?
CVE-2016-6198 affects multiple systems including certain versions of the Linux kernel, Oracle Linux, and Oracle VM Server.
Can CVE-2016-6198 be exploited remotely?
CVE-2016-6198 cannot be exploited remotely as it requires local access by an unprivileged user.