CVE-2018-1099 is a medium-severity (CVSS 5.5) Improper Input Validation vulnerability in go.etcd.io/etcd. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for go.etcd.io/etcd — see the affected versions and patch details below.
DNS Rebinding in etcd
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
go.etcd.io/etcdReal-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
DNS rebinding vulnerability found in etcd 3.3.1 and earlier. An attacker can control his DNS records to direct to localhost, and trick the browser into sending requests to localhost (or any other address).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | go.etcd.io/etcd | all versions | 3.4.0go get go.etcd.io/etcd@v3.4.0 |
Affected Products
fedorafedoraprojectetcdredhatResearch 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 go.etcd.io/etcd, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update go.etcd.io/etcd to 3.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1099 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.
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.
Configure and enable authentication on the etcd server or secure your client connection via HTTPS.Source: Red Hat security advisory for CVE-2018-1099 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2018-1099 in your dependencies?
Find it across Go, including transitive dependencies.