CVE-2016-4557 Use after free in n/a

What is CVE-2016-4557?

CVE-2016-4557 is a high-severity use after free vulnerability in Linux kernel, published on 23 May 2016. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

The replace_map_fd_with_map_ptr function in kernel/bpf/verifier.c in the Linux kernel before 4.5.5 does not properly maintain an fd data structure, which allows local users to gain privileges or cause a denial of service (use-after-free) via crafted BPF instructions that reference an incorrect file descriptor.

Which versions are affected by CVE-2016-4557?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2016-4557?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2016-4557 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-4557 exists.

Public exploit code: 1 Metasploit module and 2 Exploit-DB entries.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2016-4557, GHSA-3wq8-wfw2-w4xm, UBUNTU-CVE-2016-4557.