dbcve.org
FastnetmonApplication · Pavel Odintsov

CVE-2026-48692

HIGH · 8.1 CVSS v3.1 Published 2026-05-26
Fix available
A fix is available. Upgrade to after 1.2.9 or later.
See remediation →
86/100
Remediation priority · High
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
FastNetMon Community Edition through 1.2.9 exposes a gRPC API server on port 50052 with no authentication mechanism. The server is initialized with grpc::InsecureServerCredentials() (src/fastnetmon.cpp line 477) and a source code comment explicitly acknowledges 'Listen on the given address without any authentication mechanism.' None of the RPC methods in src/api.cpp (ExecuteBan, ExecuteUnBan, GetBanlist, GetTotalTrafficCounters, etc.) perform any credential verification. The ExecuteBan and ExecuteUnBan methods trigger security-critical actions: BGP route announcements that can blackhole network traffic, and execution of external notification scripts via popen(). An attacker with local network access can ban arbitrary IP addresses (causing denial of service to legitimate traffic), unban active attacks (disabling DDoS mitigation), and trigger script execution. There is also no role-based access control separating read-only monitoring from destructive administrative operations.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

FastNetMon Community Edition up to 1.2.9 exposes a gRPC API server on port 50052 using grpc::InsecureServerCredentials() with no authentication. The ExecuteBan and ExecuteUnBan methods can trigger BGP route announcements (blackholing traffic) and execute external scripts via popen() without any credential verification or role-based access control.

MitigationImplement gRPC authentication (TLS/mTLS or token-based), add authorization checks to all RPC methods, and restrict network access to port 50052. Consider implementing RBAC to separate read-only monitoring from administrative operations.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FastnetmonApplication
Affected:<= 1.2.9

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if FastNetMon is installed
    Check for FastNetMon process running: ps aux | grep -i fastnetmon or systemctl status fastnetmon
    Affected if FastNetMon process is running and version is 1.2.9 or lower
  2. Verify gRPC API port 50052 is listening
    Run: netstat -tlnp | grep 50052 or ss -tlnp | grep 50052 to confirm port is open and listening
    Affected if Port 50052 is open and bound to a service
  3. Check if gRPC port is network-accessible
    Run: nc -zv localhost 50052 (local) or nc -zv <target_ip> 50052 (remote) to test connectivity
    Affected if Port 50052 is reachable from untrusted network or any network-adjacent host
  4. Determine FastNetMon version
    Check installed version: fastnetmon --version or rpm -q fastnetmon or dpkg -l | grep fastnetmon
    Affected if Version is 1.2.9 or any version <= 1.2.9
  5. Inspect gRPC authentication configuration
    Review /etc/fastnetmon/fastnetmon.conf or equivalent config file for grpc_authentication, tls, or certificate settings related to port 50052
    Affected if No TLS client certificates, token-based auth, or role-based authorization is configured for the gRPC API

If FastNetMon version 1.2.9 or lower is running with port 50052 exposed and no gRPC authentication/TLS is configured, the environment is vulnerable to unauthenticated BGP manipulation and arbitrary script execution.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 1.2.9
Interim mitigation

Implement gRPC authentication (TLS/mTLS or token-based), add authorization checks to all RPC methods, and restrict network access to port 50052. Consider implementing RBAC to separate read-only monitoring from administrative operations.

Fix this in Fastnetmon Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing12.0 h
  • Review / QA8.0 h
52.0 hours of engineering $9,160
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $14,656.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-48692 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data