nebula-mesh: Host revocation is not durable - blocked/offboarded hosts can regain a valid certificate

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

4.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U · score source

EPSS

• CVE-2026-53602: 0.31% estimated exploitation activity in the next 30 days; percentile 23.79 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

9 Jul 2026, 20:52 UTC

Last modified by the source

9 Jul 2026, 20:52 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-339v-266x-79xr

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# Patch Next advisory brief: CVE-2026-53602

Advisory: nebula-mesh: Host revocation is not durable - blocked/offboarded hosts can regain a valid certificate
IDs: CVE-2026-53602, GHSA-339v-266x-79xr
Record: https://patchnext.com/advisories/cve-2026-53602 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/forgekeep/nebula-mesh 0.3.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/forgekeep/nebula-mesh: affected < 0.3.7; fixed in 0.3.7

## Suggested inspection (read-only)
- Go github.com/forgekeep/nebula-mesh: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/forgekeep/nebula-mesh.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-339v-266x-79xr (GitHub-reviewed advisory GHSA-339v-266x-79xr lists affected ranges: Go github.com/forgekeep/nebula-mesh >=0 <0.3.7)

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