How severe is CVE-2020-1758?

CVE-2020-1758 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-1758?

CVE-2020-1758 affects the following packages: org.keycloak:keycloak-parent (Maven). Ecosystems affected: Maven.

How do I fix CVE-2020-1758?

Update org.keycloak:keycloak-parent to 10.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-1758 is resolved across your whole dependency graph.

How do I detect CVE-2020-1758 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-parent, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2020-1758 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2020-1758 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-1758 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-1758?

CVE-2020-1758 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2020-1758?

CVE-2020-1758 is classified as CWE-297 (CWE-297), CWE-295 (CWE-295). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2020-1758 published, and has it been updated?

CVE-2020-1758 was published on May 15, 2020 and was last updated on August 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2020-1758 — keycloak-parent

MEDIUM

CVE-2020-1758 is a medium-severity (CVSS 5.9) CWE-297 vulnerability in org.keycloak:keycloak-parent. A fix is available for org.keycloak:keycloak-parent — see the affected versions and patch details below.

Improper Certificate Validation and Improper Validation of Certificate with Host Mismatch in Keycloak

Also known asGHSA-c597-f74m-jgc2

Published

May 15, 2020

Updated

Aug 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2020-1758 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

☕org.keycloak:keycloak-parent

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.keycloak:keycloak-parent`	all versions	10.0.0`org.keycloak:keycloak-parent:10.0.0`

Affected Products

2 products · 2 configurations

Application

keycloakredhat

< 10.0.0

range

Application

openstackredhat

1 version

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-parent, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.keycloak:keycloak-parent to 10.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-1758 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Workaround published by Red Hat

Turn off all kinds of email notifications including password reset mails.

Source: Red Hat security advisory for CVE-2020-1758 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Single Sign On 7.3.8	see advisory	RHSA-2020:2112
Red Hat Single Sign-On 7.3 for RHEL 6	`rh-sso7-keycloak-0:4.8.20-1.Final_redhat_00001.1.el6sso`	RHSA-2020:2106
Red Hat Single Sign-On 7.3 for RHEL 7	`rh-sso7-keycloak-0:4.8.20-1.Final_redhat_00001.1.el7sso`	RHSA-2020:2107
Red Hat Single Sign-On 7.3 for RHEL 8	`rh-sso7-keycloak-0:4.8.20-1.Final_redhat_00001.1.el8sso`	RHSA-2020:2108

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2020-1758 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

5.9/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE Classification

CWE-297CWE-297 CWE-295CWE-295

Weaponization

No known public exploit tooling found.

Timeline

Disclosed

May 15, 2020

Last updated

Aug 7, 2026

Identifiers

CVE-2020-1758

GHSA-c597-f74m-jgc2

References

Advisorynvd.nist.gov Reportbugzilla.redhat.com Reportissues.redhat.com

Related vulnerabilities

This CVE is medium severity; 7 of 8 other CVEs affecting keycloak-parent are rated as high or higher (top: critical).

CVE-2026-1518CVE-2026-0707CVE-2022-4137CVE-2022-3916CVE-2022-3782CVE-2022-2256CVE-2022-2668CVE-2021-3513

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedAug 7, 2026

CVE-2020-1758 — keycloak-parent

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2020-1758 in your dependencies?