{"id":"CVE-2026-53602","state":"PUBLISHED","title":"nebula-mesh - Host revocation is not durable: blocked/offboarded hosts can regain a valid certificate","description":"nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. Prior to version 0.3.7, 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. Firstly, the blocklist is 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. Secondly, 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. This issue has been patched in version 0.3.7.","publishedAt":"2026-09-04T19:40:16.908Z","updatedAt":"2026-09-04T19:50:03.057Z","severity":{"score":6.9,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["forgekeep nebula-mesh"],"affected":[{"vendor":"forgekeep","product":"nebula-mesh","versions":[{"version":"< 0.3.7","status":"affected"}]}],"references":["https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-339v-266x-79xr","https://github.com/forgekeep/nebula-mesh/issues/178","https://github.com/forgekeep/nebula-mesh/releases/tag/v0.3.7"],"weaknesses":["CWE-862","CWE-285"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53602.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53602","state":"PUBLISHED","datePublished":"2026-09-04T19:40:16.908Z","dateUpdated":"2026-09-04T19:50:03.057Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-09T19:39:52.404Z"},"containers":{"cna":{"title":"nebula-mesh - Host revocation is not durable: blocked/offboarded hosts can regain a valid certificate","descriptions":[{"lang":"en","value":"nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. Prior to version 0.3.7, 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. Firstly, the blocklist is 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. Secondly, 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. This issue has been patched in version 0.3.7."}],"affected":[{"vendor":"forgekeep","product":"nebula-mesh","versions":[{"version":"< 0.3.7","status":"affected"}]}],"references":[{"url":"https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-339v-266x-79xr","name":"https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-339v-266x-79xr","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/forgekeep/nebula-mesh/issues/178","name":"https://github.com/forgekeep/nebula-mesh/issues/178","tags":["x_refsource_MISC"]},{"url":"https://github.com/forgekeep/nebula-mesh/releases/tag/v0.3.7","name":"https://github.com/forgekeep/nebula-mesh/releases/tag/v0.3.7","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-862","lang":"en","description":"CWE-862: Missing Authorization","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-285","lang":"en","description":"CWE-285: Improper Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-04T19:40:16.908Z"},"source":{"advisory":"GHSA-339v-266x-79xr","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-04T19:49:54.943637Z","id":"CVE-2026-53602","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-04T19:50:03.057Z"}}]}}}