CVE-2021-30129
MEDIUMCVE-2021-30129 is a medium-severity (CVSS 6.5) CWE-772 vulnerability in org.apache.sshd:sshd-mina. O3 Security confirms whether CVE-2021-30129 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Buffer Overflow in Apache Mina SSHD
Real-World Exposure
org.apache.sshd:sshd-mina☕org.apache.sshd:sshd-coreReal-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
A vulnerability in sshd-core of Apache Mina SSHD allows an attacker to overflow the server causing an OutOfMemory error. This issue affects the SFTP and port forwarding features of Apache Mina SSHD version 2.0.0 and later versions. It was addressed in Apache Mina SSHD 2.7.0
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.sshd:sshd-mina | ≥ 2.0.0&&< 2.7.0 | 2.7.0 |
| ☕Maven | org.apache.sshd:sshd-core | ≥ 2.0.0&&< 2.7.0 | 2.7.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.sshd:sshd-mina. 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.apache.sshd:sshd-mina to 2.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-30129 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 CVE-2021-30129 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 CVE-2021-30129. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-30129 in your dependencies?
O3 detects CVE-2021-30129 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.