CVE-2016-4558

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2016-05-23 · updated 2026-06-17

Description

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.

Affected products

Canonical Ubuntu Linux: 14.04, 16.04
Linux kernel: from 4.4 before 4.4.11; from 4.5 before 4.5.5 — fixed in 4.4.11, 4.5.5

How to fix

Upgrade to a fixed version: Linux kernel 4.4.11, 4.5.5. Check the vendor advisory for mitigations.

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=92117d8443bc5afacc8d5ba82e541946310f106e
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.5.5
http://www.openwall.com/lists/oss-security/2016/05/06/4
http://www.ubuntu.com/usn/USN-3005-1
http://www.ubuntu.com/usn/USN-3006-1
http://www.ubuntu.com/usn/USN-3007-1
https://bugzilla.redhat.com/show_bug.cgi?id=1334303
https://github.com/torvalds/linux/commit/92117d8443bc5afacc8d5ba82e541946310f106e
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=92117d8443bc5afacc8d5ba82e541946310f106e
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.5.5
http://www.openwall.com/lists/oss-security/2016/05/06/4
http://www.ubuntu.com/usn/USN-3005-1

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