GHSA-339v-266x-79xr
GHSA-339v-266x-79xr is a CWE-285 vulnerability in github.com/forgekeep/nebula-mesh. O3 Security confirms whether GHSA-339v-266x-79xr is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
nebula-mesh: Host revocation is not durable - blocked/offboarded hosts can regain a valid certificate
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 GHSA-339v-266x-79xr.
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/forgekeep/nebula-meshReal-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
Summary
Two related authorization gaps let a host that should no longer be trusted obtain a fresh, valid Nebula certificate, because nebula-mgmt does not re-evaluate revocation/authorization state at certificate issuance time — only at poll time.
1. Blocklist not enforced at sign / re-enroll time
internal/api/enroll.go:128 calls caMgr.Sign(...) without consulting the blocklist. The blocklist is only checked in the poll path (internal/api/updates.go:57, fingerprintInBlocklist). The blocklist is keyed by certificate fingerprint (internal/store/sqlite.go), so a re-enrollment produces a new fingerprint that is not in the blocklist.
mintEnrollmentTokenForHost (internal/api/hosts.go:491) authorizes the caller via canAccessHost but does not check the host status. There is no guard preventing a blocked host from transitioning back to enrolled (internal/store/sqlite.go, enrollHostInTx updates status unconditionally).
Impact: A host that an operator has blocked can be silently un-blocked by issuing a new enrollment token and re-enrolling — it receives a fresh certificate (new fingerprint) that passes all subsequent poll-time blocklist checks. Revocation is therefore not durable. Requires an operator action (minting a re-enroll token), so this is an integrity/operational-revocation failure rather than an unauthenticated bypass.
2. Renewal does not re-validate operator / CA status
Auto-renewal at poll time (internal/api/updates.go:285-319, signHostCert) reads host.Name, host.Groups, host.NebulaIPs from the DB and re-signs without checking whether the owning operator is still active or the CA still valid. DisableOperator (internal/store/sqlite_operators.go) revokes sessions and API keys but does not retire the operator's CAs, and pki/signer.go checks only CA cert time-expiry, not operator/CA status.
Impact: A host enrolled under an operator who is later disabled continues to renew its certificate indefinitely. Offboarding an operator does not cut off the hosts they provisioned.
Affected versions
Latest tagged release (v0.3.6) and main.
Remediation
- Call a blocklist/status guard inside
handleEnrollandsignHostCertbeforecaMgr.Sign(...); refuse issuance for a host whose status isblockedor whose previous fingerprint is on the blocklist. Require an explicit unblock before re-enroll. - At renewal, re-resolve the owning operator/CA status and reject renewal if the operator is disabled or the CA retired (force re-enrollment instead).
Discovery
Found during an internal source + offensive security audit (tracking issue #178). Adversarially cross-verified against the code paths above.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/forgekeep/nebula-mesh | all versions | 0.3.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/forgekeep/nebula-mesh. 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/forgekeep/nebula-mesh to 0.3.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-339v-266x-79xr 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-339v-266x-79xr 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-339v-266x-79xr. 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-339v-266x-79xr in your dependencies?
O3 detects GHSA-339v-266x-79xr across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.