CVE-2018-19148 is a low-severity (CVSS 3.7) Information Exposure vulnerability in github.com/caddyserver/caddy. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for github.com/caddyserver/caddy — see the affected versions and patch details below.
Caddy allows enumeration of Certificates and Hostnames
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/caddyserver/caddyReal-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
Caddy through 0.11.0 sends incorrect certificates for certain invalid requests, making it easier for attackers to enumerate hostnames. Specifically, when unable to match a Host header with a vhost in its configuration, it serves the X.509 certificate for a randomly selected vhost in its configuration. Repeated requests (with a nonexistent hostname in the Host header) permit full enumeration of all certificates on the server. This generally permits an attacker to easily and accurately discover the existence of and relationships among hostnames that weren't meant to be public, though this information could likely have been discovered via other methods with additional effort.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/caddyserver/caddy | all versions | 0.11.1go get github.com/caddyserver/caddy@v0.11.1 |
Affected Products
caddycaddyserverResearch 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 github.com/caddyserver/caddy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/caddyserver/caddy to 0.11.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-19148 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
Frequently Asked Questions
Is CVE-2018-19148 in your dependencies?
Find it across Go, including transitive dependencies.