GHSA-mcg6-h362-cmq5 is a high-severity (CVSS 8.2) CWE-285 vulnerability in cobbler. 1 public exploit reference exists, so weaponization risk is real. A fix is available for cobbler — see the affected versions and patch details below.
Improper Authorization in cobbler
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
GHSA-mcg6-h362-cmq5 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 377,166 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
cobblerReal-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
Impact
If PAM is correctly configured and a user account is set to expired, the expired user-account is still able to successfully log into Cobbler in all places (Web UI, CLI & XMLRPC-API).
The same applies to user accounts with passwords set to be expired.
Patches
There is a patch for the latest Cobbler 3.3.2 available, however a backport will be done for 3.2.x.
Workarounds
- Delete expired accounts which are able to access Cobbler via PAM.
- Use
chage -l <username>to lock the account. If the account has SSH-Keys attached then remove them completely.
References
- Originally discovered by @ysf at https://www.huntr.dev/bounties/c458b868-63df-414e-af10-47e3745caa1d/
How to test if my Cobbler instance is affected?
The following pytest test assumes that your PAM setup is correct. In case the added user is not able to login, this test does not make sense to be executed.
def test_pam_login_with_expired_user():
# Arrange
# create pam testuser
test_username = "expired_user"
test_password = "password"
test_api = CobblerAPI()
subprocess_1 = subprocess.run(
["perl", "-e", "'print crypt(\"%s\", \"%s\")'" % (test_username, test_password)],
stdout=subprocess.PIPE
)
subprocess.run(["useradd", "-p", subprocess_1.stdout, test_username])
# change user to be expired
subprocess.run(["chage", "-E0", test_username])
# Act
result = pam.authenticate(test_api, test_username, test_password)
# Assert - login should fail
assert not result
For more information
If you have any questions or comments about this advisory:
- Open an issue in the Cobbler repository
- Ask in the Gitter/Matrix Chat
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | cobbler | all versions | 3.3.2pip install --upgrade 'cobbler==3.3.2' |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cobbler, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cobbler to 3.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mcg6-h362-cmq5 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 GHSA-mcg6-h362-cmq5 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-mcg6-h362-cmq5. 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.
Frequently Asked Questions
Is GHSA-mcg6-h362-cmq5 in your dependencies?
O3 Security finds GHSA-mcg6-h362-cmq5 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.