# CVE-2019-19318: Use after free in n/a

> A use-after-free in the Linux kernel allows attackers to execute arbitrary code or escalate privileges by mounting a crafted btrfs image twice.

- **Severity:** Medium 4.4 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Nov 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-19318, GHSA-r6gp-mqm3-8pv6, UBUNTU-CVE-2019-19318

## What is CVE-2019-19318?

CVE-2019-19318 is a medium-severity use after free vulnerability in Canonical Ubuntu Linux, published on 27 Nov 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel 5.3.11, mounting a crafted btrfs image twice can cause an rwsem_down_write_slowpath use-after-free because (in rwsem_can_spin_on_owner in kernel/locking/rwsem.c) rwsem_owner_flags returns an already freed pointer,

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2019-19318?

It affects 14 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Linux kernel, Netapp Active Iq Unified Manager, Netapp Aff A400 Firmware, Netapp Aff A700s Firmware, Netapp Data Availability Services, Netapp Fas8300 Firmware, Netapp Fas8700 Firmware, Netapp H610s Firmware, Netapp Hci Management Node, Netapp Solidfire, Netapp Steelstore Cloud Integrated Storage, Opensuse Leap.

## How do I fix CVE-2019-19318?

Apply the vendor's patch.

## Is CVE-2019-19318 being exploited?

There is no known exploitation of CVE-2019-19318 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-19318 and fix it if it is affected.

What it is: CVE-2019-19318 is a medium-severity use after free vulnerability in Canonical Ubuntu Linux, published on 27 Nov 2019. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-19318 in the wild and no public exploit code.

Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-19318/ (Markdown: https://insights.sbomify.com/CVE-2019-19318/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-19318
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-19318
- OSV: https://osv.dev/vulnerability/CVE-2019-19318

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-19318/
Summaries are generated and may contain mistakes; the official description above is the record.