# CVE-2019-10149: Exim Mail Transfer Agent (MTA) Improper Input Validation

> Remote attackers can execute arbitrary commands on Exim mail servers due to improper validation of recipient addresses.

- **Severity:** Critical 9.0 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 10 Jan 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 5 Jun 2019
- **Updated:** 21 Oct 2025
- **Also known as:** CLEANSTART-2025-SL34234, DEBIAN-CVE-2019-10149, DSA-4456-1, GHSA-5r7w-xvrp-rg22, UBUNTU-CVE-2019-10149, USN-4010-1, openSUSE-SU-2019:1524-1

## What is CVE-2019-10149?

CVE-2019-10149 is a critical command injection vulnerability in Canonical Ubuntu Linux, published on 5 Jun 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in Exim versions 4.87 to 4.91 (inclusive). Improper validation of recipient address in deliver_message() function in /src/deliver.c may lead to remote command execution.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2019-10149?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `exim` | openSUSE:Leap 15.0 | All versions | 4.88-lp151.4.3.1 |
| `exim` | openSUSE:Leap 15.1 | All versions | 4.88-lp151.4.3.1 |

Products: Canonical Ubuntu Linux, Debian Debian Linux, Exim Exim.

## How do I fix CVE-2019-10149?

Apply the vendor's patch. US federal agencies must fix it by 10 Jul 2022.

## Is CVE-2019-10149 being exploited?

Yes. Attackers have exploited CVE-2019-10149 in the wild since at least 10 Jan 2022.

Public exploit code:

- quick fix for CVE-2019-10149, works on Debian\Ubuntu\Centos (github_poc): https://github.com/bananaphones/exim-rce-quickfix
- CVE-2019-10149 : A flaw was found in Exim versions 4.87 to 4.91 (inclusive). Improper validation of recipient address in deliver_message() function in /src/deliver.c may lead to remote command execution. (github_poc): https://github.com/Diefunction/CVE-2019-10149
- simple python socket connection to test if exim is vulnerable to CVE-2019-10149. The payload simply touch a file in /tmp/eximrce. (github_poc): https://github.com/cowbe0x004/eximrce-CVE-2019-10149
- PoC for CVE-2019-10149, this vulnerability could be xploited betwen 4-87 to 4.91 version of Exim server. (github_poc): https://github.com/MNEMO-CERT/PoC--CVE-2019-10149_Exim
- CVE-2019-10149 privilege escalation (github_poc): https://github.com/AzizMea/CVE-2019-10149-privilege-escalation
- Instructions for installing a vulnerable version of Exim and its expluatation (github_poc): https://github.com/darsigovrustam/CVE-2019-10149

## 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-2019-10149 and fix it if it is affected.

What it is: CVE-2019-10149 is a critical command injection vulnerability in Canonical Ubuntu Linux, published on 5 Jun 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2019-10149 in the wild since at least 10 Jan 2022.

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-2019-10149/ (Markdown: https://insights.sbomify.com/CVE-2019-10149/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-10149
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-10149
- OSV: https://osv.dev/vulnerability/CVE-2019-10149

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-10149/
Summaries are generated and may contain mistakes; the official description above is the record.