# CVE-2020-16093: Security feature bypass in n/a

> LemonLDAP::NG fails to validate X.509 certificates for LDAP connections by default, allowing potential man-in-the-middle attacks.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** Yes
- **Published:** 17 Jul 2022
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-16093, GHSA-9c48-27fx-7952, UBUNTU-CVE-2020-16093

## What is CVE-2020-16093?

CVE-2020-16093 is a high-severity vulnerability in Debian Debian Linux, published on 17 Jul 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In LemonLDAP::NG (aka lemonldap-ng) through 2.0.8, validity of the X.509 certificate is not checked by default when connecting to remote LDAP backends, because the default configuration of the Net::LDAPS module for Perl is used.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2020-16093?

It affects 2 products.


Products: Debian Debian Linux, Lemonldap-Ng Lemonldap\.

## How do I fix CVE-2020-16093?

Apply the vendor's patch.

## Is CVE-2020-16093 being exploited?

There is no known exploitation of CVE-2020-16093 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-16093 and fix it if it is affected.

What it is: CVE-2020-16093 is a high-severity vulnerability in Debian Debian Linux, published on 17 Jul 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-16093 in the wild and no public exploit code.

Affected product: Debian Debian 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-2020-16093/ (Markdown: https://insights.sbomify.com/CVE-2020-16093/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-16093
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-16093
- OSV: https://osv.dev/vulnerability/CVE-2020-16093

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-16093/
Summaries are generated and may contain mistakes; the official description above is the record.