GHSA-gx3x-vq4p-mhhv
MEDIUMcert-manager-controller DoS via Specially Crafted DNS Response
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.
Blast Radius
github.com/cert-manager/cert-manager🐹github.com/cert-manager/cert-managerReal-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
The cert-manager-controller performs DNS lookups during ACME DNS-01 processing (for zone discovery and propagation self-checks). By default, these lookups use standard unencrypted DNS.
An attacker who can intercept and modify DNS traffic from the cert-manager-controller pod can insert a crafted entry into cert-manager's DNS cache. Accessing this entry will trigger a panic, resulting in Denial of Service (DoS) of the cert-manager controller.
The issue can also be exploited if the authoritative DNS server for the domain being validated is controlled by a malicious actor.
Patches
The vulnerability was introduced in cert-manager v1.18.0 and has been patched in cert-manager v1.19.3 and v1.18.5, which are the supported minor releases at the time of publishing.
cert-manager versions prior to v1.18.0 are unaffected.
Workarounds
- Using DNS-over-HTTPS reduces the risk of DNS traffic being intercepted and modified.
- Note that DNS-over-HTTPS does not prevent the risk of an attacker-controlled authoritative DNS server.
Resources
- Fix for cert-manager 1.18: https://github.com/cert-manager/cert-manager/pull/8467
- Fix for cert-manager 1.19: https://github.com/cert-manager/cert-manager/pull/8468
- Fix for master branch: https://github.com/cert-manager/cert-manager/pull/8469
Credits
Huge thanks to Oleh Konko (@1seal) for reporting the issue, providing a detailed PoC and an initial patch!
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/cert-manager/cert-manager | ≥ 1.18.0&&< 1.18.5 | 1.18.5 |
| 🐹Go | github.com/cert-manager/cert-manager | ≥ 1.19.0&&< 1.19.3 | 1.19.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/cert-manager/cert-manager. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/cert-manager/cert-manager to 1.18.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gx3x-vq4p-mhhv 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 pinpoints whether GHSA-gx3x-vq4p-mhhv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-gx3x-vq4p-mhhv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-gx3x-vq4p-mhhv in your dependencies?
O3 detects GHSA-gx3x-vq4p-mhhv across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.