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
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.
- Published
- May 15, 2020
- Updated
- Jun 16, 2026
- EPSS
- 0.9% · 58th percentile
- CWE
- CWE-297
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Report tools
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.
Affected systems
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.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Maven | org.keycloak:keycloak-parent | before 10.0.0 | 10.0.0 |
| Red Hat:red_hat_single_sign_on:7::el6 | rh-sso7-keycloak | before 0:4.8.20-1.Final_redhat_00001.1.el6sso | 0:4.8.20-1.Final_redhat_00001.1.el6sso |
| Red Hat:red_hat_single_sign_on:7::el6 | rh-sso7-keycloak-server | before 0:4.8.20-1.Final_redhat_00001.1.el6sso | 0:4.8.20-1.Final_redhat_00001.1.el6sso |
| Red Hat:red_hat_single_sign_on:7::el7 | rh-sso7-keycloak | before 0:4.8.20-1.Final_redhat_00001.1.el7sso | 0:4.8.20-1.Final_redhat_00001.1.el7sso |
| Red Hat:red_hat_single_sign_on:7::el7 | rh-sso7-keycloak-server | before 0:4.8.20-1.Final_redhat_00001.1.el7sso | 0:4.8.20-1.Final_redhat_00001.1.el7sso |
| Red Hat:red_hat_single_sign_on:7::el8 | rh-sso7-keycloak | before 0:4.8.20-1.Final_redhat_00001.1.el8sso | 0:4.8.20-1.Final_redhat_00001.1.el8sso |
| Red Hat:red_hat_single_sign_on:7::el8 | rh-sso7-keycloak-server | before 0:4.8.20-1.Final_redhat_00001.1.el8sso | 0:4.8.20-1.Final_redhat_00001.1.el8sso |
Same product
redhat: all recordsOther 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 fro39Monitor
- CVE-2022-3782keycloak: path traversal via double URL encoding.38Monitor
- CVE-2021-20195A flaw was found in keycloak in versions before 13.0.0.38Monitor
- CVE-2019-14837A flaw was found in keycloack before version 8.0.0.37Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Maven:org.keycloak:keycloak-parent | 10.0.0 | Package registry (OSV) |
| red hat:rh-sso7-keycloak | 0:4.8.20-1.Final_redhat_00001.1.el6sso · Red Hat:red_hat_single_sign_on:7::el6 | Package registry (OSV) |
| red hat:rh-sso7-keycloak-server | 0:4.8.20-1.Final_redhat_00001.1.el6sso · Red Hat:red_hat_single_sign_on:7::el6 | Package 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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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 researchersFinders, 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 MismatchCVSS 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.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.