CVE-2015-3206 is a high-severity (CVSS 8.1) Improper Authentication vulnerability in kerberos. A fix is available for kerberos — see the affected versions and patch details below.
python-kerberos vulnerable to KDC spoofing attacks
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-2015-3206 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
kerberos🐍pykerberosReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
The checkPassword function in python-kerberos does not authenticate the KDC it attempts to communicate with, which allows remote attackers to cause a denial of service (bad response), or have other unspecified impact by performing a man-in-the-middle attack.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | kerberos | all versions | No fix |
| 🐍PyPI | pykerberos | all versions | 1.1.6pip install --upgrade 'pykerberos==1.1.6' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kerberos, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
No patched version of kerberos has shipped for CVE-2015-3206 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
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-2015-3206 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2015-3206. 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-2015-3206 in your dependencies?
O3 Security finds CVE-2015-3206 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.