Missing hostname validation in Email Extension Plugin
Email Extension Plugin 2.75 and earlier does not perform hostname validation when connecting to the configured SMTP server. This lack of validation could be abused using a man-in-the-middle attack to intercept these connections.
Email Extension Plugin 2.76 validates the SMTP hostname when connecting via TLS by default. In Email Extension Plugin 2.75 and earlier, administrators can set the Java system property mail.smtp.ssl.checkserveridentity to true on startup to enable this protection. Alternatively, this protection can be enabled (or disabled in the new version) via the 'Advanced Email Properties' field in the plugin’s configuration in Configure System.
In case of problems, this protection can be disabled again by setting mail.smtp.ssl.checkserveridentity to false using either method.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.jenkins-ci.plugins:email-ext | < 2.76 | 2.76 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2020-2253
- https://github.com/jenkinsci/email-ext-plugin/commit/ac039ba581f5946975a327709ff201b459900caa
- https://github.com/jenkinsci/email-ext-plugin
- https://www.jenkins.io/security/advisory/2020-09-16/#SECURITY-1851
- http://www.openwall.com/lists/oss-security/2020/09/16/3
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N- Weakness (CWE)
CWE-295- Platform
- Java / Kotlin (Maven)
- Package
org.jenkins-ci.plugins:email-ext- Disclosed
- 24.05.2022
- Updated
- 11.10.2026 11:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-4qrj-99r6-jfrh - CC BY 4.0
Vulnerability history: org.jenkins-ci.plugins:email-ext
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 12
- First → latest
- 05.2022 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 2
- Medium 7
- Low 1
Disclosures per year
- 2022: 6
- 2023: 5
- 2024: 0
- 2025: 0
- 2026: 1
-
Missing hostname validation in Email Extension Plugin this entry
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