CVE-2019-19794 is a medium-severity (CVSS 5.9) CWE-338 vulnerability in github.com/miekg/dns. 1 public exploit reference exists, so weaponization risk is real. A fix is available for github.com/miekg/dns — see the affected versions and patch details below.
miekg/dns insecurely generates random numbers
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2019-19794 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/miekg/dnsReal-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
The miekg Go DNS package before 1.1.25, as used in CoreDNS before 1.6.6 and other products, improperly generates random numbers because math/rand is used. The TXID becomes predictable, leading to response forgeries.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/miekg/dns | all versions | 1.1.25go get github.com/miekg/dns@v1.1.25 |
Affected Products
miekg-dnsmiekg-dns_projectResearch 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/miekg/dns, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/miekg/dns to 1.1.25 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-19794 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.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Jaeger 1.20 | distributed-tracing/jaeger-rhel8-operator:1.20.1-3 | RHSA-2020:5198 |
| Red Hat OpenStack Platform 16.2 | rhosp-rhel8-tech-preview/osp-director-operator:1.2.3-2 | RHSA-2022:2183 |
Frequently Asked Questions
Is CVE-2019-19794 in your dependencies?
Find it across Go, including transitive dependencies.