# CVE-2018-19518: Command injection in n/a

> Attackers can execute arbitrary OS commands via argument injection in the IMAP Toolkit if rsh is replaced by ssh and server names are untrusted.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Nov 2018
- **Updated:** 5 Aug 2024
- **Also known as:** AZL-37053, AZL-37158, CVE-2018-1000859, DEBIAN-CVE-2018-19518, DLA-1700-1, DLA-2866-1, GHSA-5qmr-54g6-4256, MGASA-2018-0484, SUSE-SU-2018:3986-1, SUSE-SU-2018:3988-1, SUSE-SU-2018:3995-1, UBUNTU-CVE-2018-19518, USN-4160-1

## What is CVE-2018-19518?

CVE-2018-19518 is a high-severity command injection vulnerability in Canonical Ubuntu Linux, published on 25 Nov 2018. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

University of Washington IMAP Toolkit 2007f on UNIX, as used in imap_open() in PHP and other products, launches an rsh command (by means of the imap_rimap function in c-client/imap4r1.c and the tcp_aopen function in osdep/unix/tcp_unix.c) without preventing argument injection, which might allow remote attackers to execute arbitrary OS commands if the IMAP server name is untrusted input (e.g., entered by a user of a web application) and if rsh has been replaced by a program with different argument semantics. For example, if rsh is a link to ssh (as seen on Debian and Ubuntu systems), then the attack can use an IMAP server name containing a "-oProxyCommand" argument.

Weakness: CWE-88 (Improper Neutralization of Argument Delimiters in a Command)

## Which versions are affected by CVE-2018-19518?

It affects 4 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `php5` | SUSE:Linux Enterprise Module for Web and Scripting 12 | All versions | 5.5.14-109.45.2 |
| `php7` | SUSE:Linux Enterprise Module for Web and Scripting 12 | All versions | 7.0.7-50.56.2 |
| `php53` | SUSE:Linux Enterprise Server 11 SP4 | All versions | 5.3.17-112.45.1 |
| `php53` | SUSE:Linux Enterprise Server for SAP Applications 11 SP4 | All versions | 5.3.17-112.45.1 |
| `php53` | SUSE:Linux Enterprise Software Development Kit 11 SP4 | All versions | 5.3.17-112.45.1 |
| `php5` | SUSE:Linux Enterprise Software Development Kit 12 SP3 | All versions | 5.5.14-109.45.2 |
| `php7` | SUSE:Linux Enterprise Software Development Kit 12 SP3 | All versions | 7.0.7-50.56.2 |
| `php5` | SUSE:Linux Enterprise Software Development Kit 12 SP4 | All versions | 5.5.14-109.45.2 |
| `php7` | SUSE:Linux Enterprise Software Development Kit 12 SP4 | All versions | 7.0.7-50.56.2 |

Products: Canonical Ubuntu Linux, Debian Debian Linux, Php Php, Uw-Imap Project Uw-Imap.

## How do I fix CVE-2018-19518?

Apply the vendor's patch.

## Is CVE-2018-19518 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-19518 exists.

Public exploit code:

- https://github.com/houqe/EXP_CVE-2018-19518 (github_poc): https://github.com/houqe/EXP_CVE-2018-19518
- php imap_open Remote Code Execution (metasploit)
- PHP imap_open - Remote Code Execution (Metasploit) (exploitdb)
- PHP imap_open - Remote Code Execution (Metasploit) (exploitdb)
- some works on CVE-2018-19518  (github_poc): https://github.com/ensimag-security/CVE-2018-19518

## 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-2018-19518 and fix it if it is affected.

What it is: CVE-2018-19518 is a high-severity command injection vulnerability in Canonical Ubuntu Linux, published on 25 Nov 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-19518 exists.

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-2018-19518/ (Markdown: https://insights.sbomify.com/CVE-2018-19518/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-19518
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-19518
- OSV: https://osv.dev/vulnerability/CVE-2018-19518

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-19518/
Summaries are generated and may contain mistakes; the official description above is the record.