# CVE-2019-3814: Auth bypass in dovecot

> Remote attackers with valid certificates containing empty usernames can impersonate other users on Dovecot servers.

- **Severity:** High 7.7 (`CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Mar 2019
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2019-3814, DEBIAN-CVE-2019-3814, DLA-1667-1, DSA-4385-1, GHSA-2727-qgh5-485g, MGASA-2019-0072, RHSA-2019:3467, SUSE-SU-2019:0414-1, UBUNTU-CVE-2019-3814, USN-3881-1, openSUSE-SU-2019:0243-1

## What is CVE-2019-3814?

CVE-2019-3814 is a high-severity authentication bypass vulnerability in Canonical Ubuntu Linux, published on 27 Mar 2019. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

It was discovered that Dovecot before versions 2.2.36.1 and 2.3.4.1 incorrectly handled client certificates. A remote attacker in possession of a valid certificate with an empty username field could possibly use this issue to impersonate other users.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2019-3814?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `dovecot` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-mysql` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-mysql-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-pgsql` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-pgsql-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-pigeonhole` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot-pigeonhole-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.2.36-10.el8 |
| `dovecot` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.2.36-10.el8 |
| `dovecot-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.2.36-10.el8 |
| `dovecot-debugsource` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.2.36-10.el8 |
| `dovecot-devel` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.2.36-10.el8 |
| `dovecot-mysql-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.2.36-10.el8 |
| `dovecot-pgsql-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.2.36-10.el8 |
| `dovecot-pigeonhole-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.2.36-10.el8 |
| `dovecot23` | SUSE:Linux Enterprise Module for Server Applications 15 | All versions | 2.3.3-4.7.4 |

Products: Canonical Ubuntu Linux, Dovecot Dovecot, Opensuse Leap.

## How do I fix CVE-2019-3814?

Upgrade to a fixed version.

## Is CVE-2019-3814 being exploited?

There is no known exploitation of CVE-2019-3814 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-2019-3814 and fix it if it is affected.

What it is: CVE-2019-3814 is a high-severity authentication bypass vulnerability in Canonical Ubuntu Linux, published on 27 Mar 2019. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-3814 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-2019-3814/ (Markdown: https://insights.sbomify.com/CVE-2019-3814/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-3814
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-3814
- OSV: https://osv.dev/vulnerability/CVE-2019-3814

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-3814/
Summaries are generated and may contain mistakes; the official description above is the record.