vulnerability / NVI-00018400 / Revision 1
nebula-mesh: Host advanced overrides allow YAML injection into agent config.yml
GitHub lists this reviewed advisory for github.com/juev/nebula-mesh. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/juev/nebula-mesh
source listed< 0.3.2
`internal/configgen/generator.go:86,108,119` interpolates the operator-supplied `ListenHost` and `TunDevice` fields raw into a `text/template` that produces the agent's `config.yml`. `internal/web/advanced.go:20-35` accepts both with only `strings.TrimSpace` — no character or shape validation. ## Exploit An operator (or attacker with any operator key, given the cross-tenant CRUD advisory) sets `adv_tun_device` to: ``` nebula0 lighthouse: am_lighthouse: true hosts: ["10.0.0.1"] # ``` The agent fetches the rendered config on its next signed poll. On config reload, it loads the injected YAML keys: the host self-promotes to lighthouse, attracts mesh traffic, or sets `am_relay: true` to be selected as a relay. The `ListenHost` field has the same shape. ## Affected All released versions prior to v0.3.2. ## Threat model - **Today**: operator can compromise their own host's config (trivially allowed if they own the host, but they can also set lighthouse/relay flags that the operator-create form does NOT expose — privilege uplift within their own tenant). - **Combined with the critical /api/v1 authz advisory**: any operator key can mutate ANOTHER tenant's host overrides and inject
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-7hp6-g3pq-3pc3 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
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