CVE-2025-55740 — nginx-defender
MEDIUMCVE-2025-55740 is a medium-severity (CVSS 6.5) CWE-1392 vulnerability in github.com/Anipaleja/nginx-defender. A fix is available for github.com/Anipaleja/nginx-defender — see the affected versions and patch details below.
Default Credentials in nginx-defender Configuration Files
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-55740.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/Anipaleja/nginx-defenderReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
This is a configuration vulnerability affecting nginx-defender deployments. Example configuration files
config.yaml, docker-compose.yml contain default credentials (default_password: "change_me_please", GF_SECURITY_ADMIN_PASSWORD=admin123). If users deploy nginx-defender without changing these defaults, attackers with network access could gain administrative control, bypassing security protections.
Who is impacted? All users who deploy nginx-defender with default credentials and expose the admin interface to untrusted networks.
Patches
The issue is addressed in v1.5.0 and later.
Startup warnings are added if default credentials are detected. Documentation now strongly recommends changing all default passwords before deployment. Patched versions: 1.5.0 and later Will be fully patched in v1.7.0 and later
Workarounds
Users can remediate the vulnerability without upgrading by manually changing all default credentials in configuration files before deployment:
# config.yaml
auth:
default_password: "your_strong_password_here"
# docker-compose.yml
- GF_SECURITY_ADMIN_PASSWORD=your_strong_password
Restrict access to the admin interface and use environment variables for secrets.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/Anipaleja/nginx-defender | all versions | 1.5.0go get github.com/Anipaleja/nginx-defender@v1.5.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/Anipaleja/nginx-defender, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/Anipaleja/nginx-defender to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55740 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.
Frequently Asked Questions
Is CVE-2025-55740 in your dependencies?
Find it across Go, including transitive dependencies.