CVE-2019-15792 Type confusion in shiftfs

What is CVE-2019-15792?

CVE-2019-15792 is a high-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 23 Apr 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, shiftfs_btrfs_ioctl_fd_replace() calls fdget(oldfd), then without further checks passes the resulting file* into shiftfs_real_fdget(), which casts file->private_data, a void* that points to a filesystem-dependent type, to a "struct shiftfs_file_info *". As the private_data is not required to be a pointer, an attacker can use this to cause a denial of service or possibly execute arbitrary code.

Weakness: CWE-843

Which versions are affected by CVE-2019-15792?

It affects 2 products.

Products include Canonical Ubuntu Linux, Linux kernel.

How do I fix CVE-2019-15792?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2019-15792 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-15792 exists.

Public exploit code: 1 Exploit-DB entry.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

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

Also known as GHSA-rx63-pxf9-gqg8, UBUNTU-CVE-2019-15792.