# CVE-2018-20685: Missing authorization in n/a

> Remote SSH servers can bypass access restrictions to modify target directory permissions on the client side via crafted filenames.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 10 Jan 2019
- **Updated:** 17 Dec 2025
- **Also known as:** ALPINE-CVE-2018-20685, DEBIAN-CVE-2018-20685, GHSA-28hp-2gv6-gjp8, MGASA-2019-0067, UBUNTU-CVE-2018-20685

## What is CVE-2018-20685?

CVE-2018-20685 is a medium-severity missing authorization vulnerability in Canonical Ubuntu Linux, published on 10 Jan 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In OpenSSH 7.9, scp.c in the scp client allows remote SSH servers to bypass intended access restrictions via the filename of . or an empty filename. The impact is modifying the permissions of the target directory on the client side.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2018-20685?

It affects 22 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Fujitsu M10-1 Firmware, Fujitsu M10-4 Firmware, Fujitsu M10-4s Firmware, Fujitsu M12-1 Firmware, Fujitsu M12-2 Firmware, Fujitsu M12-2s Firmware, Netapp Cloud Backup, Netapp Element Software, Netapp Ontap Select Deploy, Netapp Steelstore Cloud Integrated Storage, Netapp Storage Automation Store, OpenSSH, Oracle Solaris, Redhat Enterprise Linux, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Tus, Siemens Scalance X204rna Eec Firmware and 2 more.

## How do I fix CVE-2018-20685?

Upgrade to a fixed version.

## Is CVE-2018-20685 being exploited?

There is no known exploitation of CVE-2018-20685 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-2018-20685 and fix it if it is affected.

What it is: CVE-2018-20685 is a medium-severity missing authorization vulnerability in Canonical Ubuntu Linux, published on 10 Jan 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-20685 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-2018-20685/ (Markdown: https://insights.sbomify.com/CVE-2018-20685/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20685
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20685
- OSV: https://osv.dev/vulnerability/CVE-2018-20685

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20685/
Summaries are generated and may contain mistakes; the official description above is the record.