GHSA-6fr3-286q-q3cr is a medium-severity (CVSS 4.8) CWE-295 vulnerability in org.jenkins-ci.plugins:mailer. O3 Security confirms whether GHSA-6fr3-286q-q3cr is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Improper Validation of Certificate with Host Mismatch in Jenkins Mailer Plugin
Real-World Exposure
org.jenkins-ci.plugins:mailer☕org.jenkins-ci.plugins:mailer☕org.jenkins-ci.plugins:mailerReal-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
Jenkins Mailer Plugin prior to 1.32.1, 1.31.1, and 1.29.1 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.
Mailer Plugin 1.32.1, 1.31.1, and 1.29.1 validates the SMTP hostname when connecting via TLS by default. In Mailer Plugin 1.32 and earlier, administrators can set the Java system property mail.smtp.ssl.checkserveridentity to true on startup to enable this protection.
In case of problems, this protection can be disabled again by setting the Java system property mail.smtp.ssl.checkserveridentity to false on startup.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.jenkins-ci.plugins:mailer | ≥ 1.32&&< 1.32.1 | 1.32.1 |
| ☕Maven | org.jenkins-ci.plugins:mailer | ≥ 1.30&&< 1.31.1 | 1.31.1 |
| ☕Maven | org.jenkins-ci.plugins:mailer | all versions | 1.29.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:mailer. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.jenkins-ci.plugins:mailer to 1.32.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6fr3-286q-q3cr 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.
How O3 protects you
O3 pinpoints whether GHSA-6fr3-286q-q3cr is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-6fr3-286q-q3cr. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-6fr3-286q-q3cr in your dependencies?
O3 detects GHSA-6fr3-286q-q3cr across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.