CVE-2020-11050
Improper Validation of Certificate with Host Mismatch in Java-WebSocket
In Java-WebSocket less than or equal to 1.4.1, there is an Improper Validation of Certificate with Host Mismatch where WebSocketClient does not perform SSL hostname validation. This has been patched in 1.5.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Improper Validation of Certificate with Host Mismatch in Java-WebSocket
In Java-WebSocket less than or equal to 1.4.1, there is an Improper Validation of Certificate with Host Mismatch where WebSocketClient does not perform SSL hostname validation. This has been patched in 1.5.0.
- Record
CVE-2020-11050- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-297
- Updated
- 2026-11-02
EUVDEUVD-2020-0424
In Java-WebSocket less than or equal to 1.4.1, there is an Improper Validation of Certificate with Host Mismatch where WebSocketClient does not perform SSL hostname validation. This has been patched in 1.5.0.
- Record
EUVD-2020-0424- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-gw55-jm4h-x339
Improper Validation of Certificate with Host Mismatch in Java-WebSocket
The Java-WebSocket Client does not perform hostname verification.
- This means that SSL certificates of other hosts are accepted as long as they are trusted. To exploit this vulnerability an attacker has to perform a man-in-the-middle (MITM) attack between a Java application using the Java-WebSocket Client and an WebSocket server it's connecting to.
- TLS normally protects users and systems against MITM attacks, it cannot if certificates from other trusted hosts are accepted by the client.
For more information see: CWE-297: Improper Validation of Certificate with Host Mismatch - https://cwe.mitre.org/data/definitions/297.html
Important note
The OWASP Dependency-Check (https://jeremylong.github.io/DependencyCheck/index.html) may report that a dependency of your project is affected by this security vulnerability, but you don't use this lib. This is caused by the fuzzy search in the OWASP implementation. Check out this issue (https://github.com/TooTallNate/Java-WebSocket/issues/1019#issuecomment-628507934) for more information and a way to suppress the warning.
- Record
GHSA-gw55-jm4h-x339- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-295, CWE-297
- Updated
- 2026-11-02
NVD
In Java-WebSocket less than or equal to 1.4.1, there is an Improper Validation of Certificate with Host Mismatch where WebSocketClient does not perform SSL hostname validation. This has been patched in 1.5.0.
- Record
CVE-2020-11050- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-297, CWE-295
- Updated
- 2026-11-02
OSV
In Java-WebSocket less than or equal to 1.4.1, there is an Improper Validation of Certificate with Host Mismatch where WebSocketClient does not perform SSL hostname validation. This has been patched in 1.5.0.
- Record
CVE-2020-11050- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-gw55-jm4h-x339
Improper Validation of Certificate with Host Mismatch in Java-WebSocket
The Java-WebSocket Client does not perform hostname verification.
- This means that SSL certificates of other hosts are accepted as long as they are trusted. To exploit this vulnerability an attacker has to perform a man-in-the-middle (MITM) attack between a Java application using the Java-WebSocket Client and an WebSocket server it's connecting to.
- TLS normally protects users and systems against MITM attacks, it cannot if certificates from other trusted hosts are accepted by the client.
For more information see: CWE-297: Improper Validation of Certificate with Host Mismatch - https://cwe.mitre.org/data/definitions/297.html
Important note
The OWASP Dependency-Check (https://jeremylong.github.io/DependencyCheck/index.html) may report that a dependency of your project is affected by this security vulnerability, but you don't use this lib. This is caused by the fuzzy search in the OWASP implementation. Check out this issue (https://github.com/TooTallNate/Java-WebSocket/issues/1019#issuecomment-628507934) for more information and a way to suppress the warning.
- Record
GHSA-gw55-jm4h-x339- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-295, CWE-297
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.java-websocket:Java-WebSocketMaven |
through 1.4.1 | 1.5.0 |
org.java-websocket:Java-WebSocketMaven |
before 1.5.0, plus listed versions 1.3.01.3.41.3.51.3.61.3.7 Show 4 moreShow less1.3.81.3.91.4.01.4.1 |
1.5.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-11050 is a critical vulnerability (CVSS 9.0) in Java-websocket Project Java-websocket, published May 7, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.79%, the 56th percentile. Fixed in org.java-websocket:Java-WebSocket 1.5.0.