CVE-2026-53604

CVE-2026-53604 is a high-severity vulnerability with a CVSS 4.0 base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-212.

Key facts

Description

nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. Prior to version 0.3.8, the web handler renderMobileBundle passes the real *pki.CAResolver directly into mobilebundle.Build. Inside Build, resolver.LoadByID decrypts the CA's ed25519 private key into a *pki.CAManager, but Build never calls CAManager.Wipe() on any return path. As a result, when a mobile-bundle request goes through the web UI and Build returns — especially on error (missing network, invalid prefix, DB error, signing failure) — the plaintext CA private key remains on the Go heap, unwiped, until garbage collection. An attacker able to read process memory (core dump, swap, memory-scraping) can recover the CA signing key, which would allow minting arbitrary host certificates for the mesh. The API handler already does this correctly: it loads the CAManager, defer caMgr.Wipe(), and wraps it in caManagerResolver. Only the web path is affected. This issue has been patched in version 0.3.8.

Frequently asked questions

What is CVE-2026-53604?
nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. Prior to version 0.3.8, the web handler renderMobileBundle passes the real *pki.CAResolver directly into mobilebundle.Build. Inside Build, resolver.LoadByID decrypts the CA's ed25519 private key into a *pki.CAManager, but Build never calls CAManager.Wipe() on any return path. As a result, when a mobile-bundle request goes through the web UI and Build returns — especially on error (missing network, invalid prefix, DB error, signing failure) — the plaintext CA private key remains on the Go heap, unwiped, until garbage collection. An attacker able to read process memory (core dump, swap, memory-scraping) can recover the CA signing key, which would allow minting arbitrary host certificates for the mesh. The API handler already does this correctly: it loads the CAManager, defer caMgr.Wipe(), and wraps it in caManagerResolver. Only the web path is affected. This issue has been patched in version 0.3.8.
How severe is CVE-2026-53604?
CVE-2026-53604 has a CVSS 4.0 base score of 7.1, rated high severity.
Is CVE-2026-53604 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-53604?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-53604 published?
CVE-2026-53604 was published on 2026-09-04 and last updated on 2026-09-08.

References

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