# CVE-2020-1758: Improper Certificate Validation and Improper Validation of Certificate with Host Mismatch in Keycloak

> Attackers can intercept SMTP emails via man-in-the-middle attacks due to missing TLS hostname verification in Keycloak.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/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:** 15 May 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-c597-f74m-jgc2

## What is CVE-2020-1758?

CVE-2020-1758 is a medium-severity vulnerability in Redhat Keycloak, published on 15 May 2020. 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

A flaw was found in Keycloak in versions before 10.0.0, where it does not perform the TLS hostname verification while sending emails using the SMTP server. This flaw allows an attacker to perform a man-in-the-middle (MITM) attack.

Weakness: CWE-295 (Improper Certificate Validation), CWE-297 (Improper Validation of Certificate with Host Mismatch)

## Which versions are affected by CVE-2020-1758?

2 open source packages ship an affected version, including org.keycloak:keycloak-parent. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.keycloak:keycloak-parent` | Maven | All versions | 10.0.0 |
| `org.keycloak:keycloak-parent` | Maven | All versions | 10.0.0 |

Products: Redhat Keycloak, Redhat Openstack.

## How do I fix CVE-2020-1758?

Upgrade org.keycloak:keycloak-parent to 10.0.0 or later.

## Is CVE-2020-1758 being exploited?

There is no known exploitation of CVE-2020-1758 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Keycloak

- [CVE-2022-4361](https://insights.sbomify.com/CVE-2022-4361/): Keycloak vulnerable to cross-site scripting when validating URI-schemes on SAML and OIDC (critical 10.0)
- [CVE-2022-1245](https://insights.sbomify.com/CVE-2022-1245/): Keycloak vulnerable to privilege escalation on Token Exchange feature (critical 9.8)
- [CVE-2021-20195](https://insights.sbomify.com/CVE-2021-20195/): keycloak Self Stored Cross-site Scripting vulnerability (critical 9.6)
- [CVE-2019-14910](https://insights.sbomify.com/CVE-2019-14910/): Keycloak Authentication Error (critical 9.3)
- [CVE-2019-14909](https://insights.sbomify.com/CVE-2019-14909/): Keycloak Authentication Error (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-1758 and fix it if it is affected.

What it is: CVE-2020-1758 is a medium-severity vulnerability in Redhat Keycloak, published on 15 May 2020. 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-2020-1758 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.keycloak:keycloak-parent (Maven): affected all versions; fixed in 10.0.0
- org.keycloak:keycloak-parent (Maven): affected all versions; fixed in 10.0.0

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-2020-1758/ (Markdown: https://insights.sbomify.com/CVE-2020-1758/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-1758
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-1758
- OSV: https://osv.dev/vulnerability/CVE-2020-1758

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-1758/
Summaries are generated and may contain mistakes; the official description above is the record.