nebula-mesh: Session and OIDC state cookies lack the Secure attribute

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.2, internal/web/session.go and internal/web/oidc.go set HttpOnly and SameSite=Lax on every cookie but never Secure. A single plaintext request to the origin (operator on a LAN, mistyped URL, HTTP→HTTPS not strictly enforced, reverse proxy misconfiguration) discloses the session. This issue has been patched in version 0.3.2.

Source published

28 Jul 2026 18:47:57 UTC

Source modified

28 Jul 2026 19:16:39 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 4.6 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U

nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.2, internal/web/session.go and internal/web/oidc.go set HttpOnly and SameSite=Lax on every cookie but never Secure. A single plaintext request to the origin (operator on a LAN, mistyped URL, HTTP→HTTPS not strictly enforced, reverse proxy misconfiguration) discloses the session. This issue has been patched in version 0.3.2.

Source published

28 Jul 2026 19:17:34 UTC

Source modified

23 Oct 2026 23:10:00 UTC

Observed here

25 Oct 2026 12:17:26 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 4.6 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

`internal/web/session.go` and `internal/web/oidc.go` set `HttpOnly` and `SameSite=Lax` on every cookie but never `Secure`. A single plaintext request to the origin (operator on a LAN, mistyped URL, HTTP→HTTPS not strictly enforced, reverse proxy misconfiguration) discloses the session. ## Affected All released versions up to v0.3.1. ## Impact An attacker who can observe one HTTP request to the origin recovers the session cookie and impersonates the operator for the remainder of its 24h TTL. The OIDC state cookie has a narrower 10-minute window but enables CSRF on the OIDC callback during that window. ## Cookie sites - `internal/web/session.go` — `Login`, `StartAuthenticatedSession`, `CompleteTwoFactor`, `Logout` - `internal/web/oidc.go` — `HandleLogin` (state set), `HandleCallback` (state clear) ## Suggested fix Driven by an explicit `cookie_secure` config option, inferred true when `tls_cert`+`tls_key` are configured and false otherwise. `rate_limit.trust_proxy_header` is deliberately not used as a signal — that flag controls XFF parsing for rate-limit IPs and does not promise the proxy speaks TLS to clients. Operator behind a TLS-terminating proxy sets `cookie_secure: true` explicitly. Logout and OIDC state-clear cookies also pick up matching `HttpOnly` + `SameSite=Lax` so browsers reliably replace the original. ## Reproducer Start `nebula-mgmt` without `tls_cert`/`tls_key` (the documented "behind a reverse proxy" deployment). Hit any login flow over the local listener: ``` curl -i -X POST -d 'username=admin&password=…' http://127.0.0.1:8080/ui/login ``` The `Set-Cookie: nebula_session=…` line will lack `Secure`. A subsequent unencrypted hop reveals the cookie verbatim. ## Operational migration Operators flipping `cookie_secure` on a running deployment should expect a one-time logout: existing browser cookies have the old attribute set and the new delete-cookie won't match.

Source published

10 Jun 2026 18:49:22 UTC

Source modified

25 Jun 2026 23:11:33 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U

Publisher rating · MODERATE

nebula-mesh: Session and OIDC state cookies lack the Secure attribute in github.com/juev/nebula-mesh

Source published

25 Jun 2026 22:34:38 UTC

Source modified

25 Jun 2026 23:01:25 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.