CVE-2019-15791: Reference count underflow in shiftfs
First published: Thu Apr 23 2020(Updated: )
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() installs an fd referencing a file from the lower filesystem without taking an additional reference to that file. After the btrfs ioctl completes this fd is closed, which then puts a reference to that file, leading to a refcount underflow.
Credit: security@ubuntu.com security@ubuntu.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | =5.0 | |
| Linux Linux kernel | =5.3 | |
| Canonical Ubuntu Linux | =18.04 | |
| Canonical Ubuntu Linux | =19.04 | |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.119-1 6.11.10-1 6.12.5-1 |
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Reference Links
- https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=601a64857b3d7040ca15c39c929e6b9db3373ec1
- https://usn.ubuntu.com/usn/usn-4183-1
- https://usn.ubuntu.com/usn/usn-4184-1
- https://launchpad.net/bugs/cve/CVE-2019-15791
- https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1850867
- https://security-tracker.debian.org/tracker/CVE-2019-15791
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-15791
- https://nvd.nist.gov/vuln/detail/CVE-2019-15791
- https://ubuntu.com/security/CVE-2019-15791
Frequently Asked Questions
What is CVE-2019-15791?
CVE-2019-15791 is a vulnerability in shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series.
Which software versions are affected by CVE-2019-15791?
CVE-2019-15791 affects Ubuntu Linux versions 2.6.12~ up to, but not including, 5.3.0-22.24.
How can I fix the CVE-2019-15791 vulnerability?
To fix the CVE-2019-15791 vulnerability, update your Ubuntu Linux kernel to version 5.3.0-22.24 or higher.
Are there any references for CVE-2019-15791?
Yes, you can find references for CVE-2019-15791 at the following links: [Reference 1](https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=601a64857b3d7040ca15c39c929e6b9db3373ec1), [Reference 2](https://usn.ubuntu.com/usn/usn-4183-1), [Reference 3](https://usn.ubuntu.com/usn/usn-4184-1).
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