CVE-2026-6720
Fix: projectcalico/calico#12535CVE-2026-6720 is a CWE-532 vulnerability in github.com/projectcalico/calicoctl/v3. O3 Security confirms whether CVE-2026-6720 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Calicoctl leaks cluster credentials to stderr when verbose logging is enabled
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-2026-6720.
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.
Real-World Exposure
github.com/projectcalico/calicoctl/v3Real-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
When calicoctl is invoked with --log-level=info or --log-level=debug, the client prints the full contents of its loaded connection-configuration struct to stderr in a single log line. The struct embeds every credential calicoctl uses to talk to the cluster — inline kubeconfig (with bearer token), Kubernetes API bearer token, etcd password, and inline PEM-encoded etcd client certificate and key. Any reader of that stderr stream — CI job logs, session-recording archives, shared support-ticket transcripts, or local filesystem viewers on the host that ran calicoctl — can extract these credentials with zero Kubernetes privilege. calicoctl's default log level is panic, so this issue only triggers when verbose logging is explicitly enabled.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/projectcalico/calicoctl/v3 | all versions | 3.31.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/projectcalico/calicoctl/v3. 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/projectcalico/calicoctl/v3 to 3.31.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-6720 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 CVE-2026-6720 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 CVE-2026-6720. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-6720 in your dependencies?
O3 detects CVE-2026-6720 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.