CVE-2016-4558: Use After Free
A flaw was found in the Linux kernels implementation of BPF in which systems with more than 32GB of physical memory and unlimited RLIMITMEMLOCK settings an application can overflow a 32 bit refcount.
Additionally in the same environment, malicious applications can overflow a map refcount on larger memory (1Tb). When the overflow wraps to zero a reference can be held while being free'd. This can lead to a use after free
CVE assignment:
http://seclists.org/oss-sec/2016/q2/266
Upstream fix:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=92117d8443bc5afacc8d5ba82e541946310f106e
Other sources
The BPF subsystem in the Linux kernel before 4.5.5 mishandles reference counts, which allows local users to cause a denial of service (use-after-free) or possibly have unspecified other impact via a crafted application on (1) a system with more than 32 Gb of memory, related to the program reference count or (2) a 1 Tb system, related to the map reference count.
— Launchpad
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the vulnerability ID of this vulnerability?
The vulnerability ID is CVE-2016-4558.
What is the severity level of CVE-2016-4558?
The severity level of CVE-2016-4558 is high.
How does CVE-2016-4558 affect Linux systems?
CVE-2016-4558 can cause a denial of service (use-after-free) or possibly have unspecified other impact via a crafted application on systems with more than 32 Gb of memory.
Which versions of the Linux kernel are affected by CVE-2016-4558?
Linux kernel versions before 4.5.5 are affected by CVE-2016-4558.
How can I fix CVE-2016-4558?
To fix CVE-2016-4558, update your Linux kernel to version 4.5.5 or later.