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NVD / CVE Program· CNA redhat

CVE-2020-1758: 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 t

Noroxi assessment

Priority: Monitor (action score 23/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.92% (FIRST EPSS); higher than 60.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: org.keycloak:keycloak-parent (Maven) 10.0.0; rh-sso7-keycloak (Red Hat:red_hat_single_sign_on:7::el6) 0:4.8.20-1.Final_redhat_00001.1.el6sso; rh-sso7-keycloak-server (Red Hat:red_hat_single_sign_on:7::el6) 0:4.8.20-1.Final_redhat_00001.1.el6sso.

Low priority for now. Upgrade to org.keycloak:keycloak-parent (Maven) 10.0.0; rh-sso7-keycloak (Red Hat:red_hat_single_sign_on:7::el6) 0:4.8.20-1.Final_redhat_00001.1.el6sso; rh-sso7-keycloak-server (Red Hat:red_hat_single_sign_on:7::el6) 0:4.8.20-1.Final_redhat_00001.1.el6sso or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.9 · v3.1—No exploit Fix available
Published
May 15, 2020
Updated
Jun 16, 2026
EPSS
0.9% · 60th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.9%

CNA vs NVD score

NVD
5.9
CNA · redhat
5.3
0.6 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2020-1758

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
redhatkeycloak
redhatopenstack

Check your site's encryption

This vulnerability is about certificate validation or weak cryptography. The free SSL checker tests your certificate, enabled TLS versions and weak ciphers.

Run the SSL check

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • redhat keycloakbefore 10.0.0
  • redhat openstack10

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat keycloak

    • keycloak versions before 10.0.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.keycloak:keycloak-parentbefore 10.0.010.0.0
Red Hat:red_hat_single_sign_on:7::el6rh-sso7-keycloakbefore 0:4.8.20-1.Final_redhat_00001.1.el6sso0:4.8.20-1.Final_redhat_00001.1.el6sso
Red Hat:red_hat_single_sign_on:7::el6rh-sso7-keycloak-serverbefore 0:4.8.20-1.Final_redhat_00001.1.el6sso0:4.8.20-1.Final_redhat_00001.1.el6sso
Red Hat:red_hat_single_sign_on:7::el7rh-sso7-keycloakbefore 0:4.8.20-1.Final_redhat_00001.1.el7sso0:4.8.20-1.Final_redhat_00001.1.el7sso
Red Hat:red_hat_single_sign_on:7::el7rh-sso7-keycloak-serverbefore 0:4.8.20-1.Final_redhat_00001.1.el7sso0:4.8.20-1.Final_redhat_00001.1.el7sso
Red Hat:red_hat_single_sign_on:7::el8rh-sso7-keycloakbefore 0:4.8.20-1.Final_redhat_00001.1.el8sso0:4.8.20-1.Final_redhat_00001.1.el8sso
Red Hat:red_hat_single_sign_on:7::el8rh-sso7-keycloak-serverbefore 0:4.8.20-1.Final_redhat_00001.1.el8sso0:4.8.20-1.Final_redhat_00001.1.el8sso

Same product

redhat: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-10770A flaw was found in Keycloak before 13.0.0, where it is possible to force the server to call out an unverified URL using the OIDC parameter
    42Plan
  • CVE-2022-1245A privilege escalation flaw was found in the token exchange feature of keycloak.
    39Monitor
  • CVE-2019-14910A vulnerability was found in keycloak 7.x, when keycloak is configured with LDAP user federation and StartTLS is used instead of SSL/TLS fro
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2020-1724May 11, 2020 · A flaw was found in Keycloak in versions before 9.0.2.
    17Monitor
  • ← EarlierCVE-2020-1714May 13, 2020 · A flaw was found in Keycloak before version 11.0.0, where the code base contains usages of ObjectInputStream without type checks.
    36Monitor
  • Later →CVE-2020-1727Jun 22, 2020 · A vulnerability was found in Keycloak before 9.0.2, where every Authorization URL that points to an IDP server lacks proper input validation
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Maven:org.keycloak:keycloak-parent10.0.0Package registry (OSV)
red hat:rh-sso7-keycloak0:4.8.20-1.Final_redhat_00001.1.el6sso · Red Hat:red_hat_single_sign_on:7::el6Package registry (OSV)
red hat:rh-sso7-keycloak-server0:4.8.20-1.Final_redhat_00001.1.el6sso · Red Hat:red_hat_single_sign_on:7::el6Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-297 · Improper Validation of Certificate with Host Mismatch

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records