CVE-2021-30129 — sshd-mina
MEDIUMCVE-2021-30129 is a medium-severity (CVSS 6.5) CWE-772 vulnerability in org.apache.sshd:sshd-mina. A fix is available for org.apache.sshd:sshd-mina — see the affected versions and patch details below.
Buffer Overflow in Apache Mina SSHD
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2021-30129 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 | 2.7.0org.apache.sshd:sshd-mina:2.7.0 |
| ☕Maven | org.apache.sshd:sshd-core | ≥ 2.0.0&&< 2.7.0 | 2.7.0org.apache.sshd:sshd-core: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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-30129 can be triaged on real exposure rather than presence alone.
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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat OpenStack Platform's OpenDaylight will not be updated for this flaw because it was deprecated as of OpenStack Platform 14 and is only receiving security fixes for Critical flaws.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Fuse 7.10 | sshd-core | RHSA-2021:5134 |
| Red Hat JBoss Enterprise Application Platform | org.apache.sshd/sshd-core:2.7.0.redhat-00001 | RHSA-2021:4679 |
| Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 8 | eap7-apache-sshd-0:2.7.0-1.redhat_00001.1.el8eap | RHSA-2021:4677 |
| Red Hat JBoss Enterprise Application Platform 7.4 on RHEL 7 | eap7-apache-sshd-0:2.7.0-1.redhat_00001.1.el7eap | RHSA-2021:4676 |
| RHINT Camel-Q 2.2.1 | see advisory | RHSA-2022:1013 |
| RHPAM 7.13.4 async | sshd-core | RHSA-2023:4983 |
Frequently Asked Questions
Is CVE-2021-30129 in your dependencies?
O3 Security finds CVE-2021-30129 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.