# CVE-2018-16866: Information disclosure in systemd

> A local attacker can exploit an out-of-bounds read in systemd-journald to disclose process memory data.

- **Severity:** Medium 4.3 (`CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Jan 2019
- **Updated:** 9 Jun 2025
- **Also known as:** DEBIAN-CVE-2018-16866, GHSA-jr8q-jw7m-4m3m, UBUNTU-CVE-2018-16866

## What is CVE-2018-16866?

CVE-2018-16866 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 11 Jan 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An out of bounds read was discovered in systemd-journald in the way it parses log messages that terminate with a colon ':'. A local attacker can use this flaw to disclose process memory data. Versions from v221 to v239 are vulnerable.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2018-16866?

It affects 21 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Netapp Active Iq Performance Analytics Services, Netapp Element Software, Redhat Enterprise Linux, Redhat Enterprise Linux Compute Node Eus, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux for Ibm Z Systems \(Structure A\), Redhat Enterprise Linux for Ibm Z Systems Eus, Redhat Enterprise Linux for Power Big Endian, Redhat Enterprise Linux for Power Big Endian Eus, Redhat Enterprise Linux for Power Little Endian, Redhat Enterprise Linux for Power Little Endian Eus, Redhat Enterprise Linux for Scientific Computing, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server for Power Little Endian Update Services for Sap Solutions, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Server Update Services for Sap Solutions, Redhat Enterprise Linux Workstation and 1 more.

## How do I fix CVE-2018-16866?

Apply the vendor's patch.

## Is CVE-2018-16866 being exploited?

There is no known exploitation of CVE-2018-16866 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-2018-16866 and fix it if it is affected.

What it is: CVE-2018-16866 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 11 Jan 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-2018-16866 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-2018-16866/ (Markdown: https://insights.sbomify.com/CVE-2018-16866/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-16866
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-16866
- OSV: https://osv.dev/vulnerability/CVE-2018-16866

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-16866/
Summaries are generated and may contain mistakes; the official description above is the record.