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🛡️ CVE-2026-48692 on Ubuntu — fastnetmon

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

Distribution advisory

This page covers CVE-2026-48692 as tracked by Ubuntu, for the package fastnetmon. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached from an adjacent network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

  • Attack vector: Adjacent network — the attacker has to sit on the same local or logical network.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

UBUNTU-CVE-2026-48692 is classified as CWE-306: Missing Authentication for Critical Function. A sensitive function can be reached without authenticating at all.

Affected software

UBUNTU-CVE-2026-48692 is recorded against 1 package.

  • fastnetmon

Timeline and source

Published on 26 May 2026 and last revised on 15 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
lorikeetsecurity.com (Report)
github.com (Report)
github.com (Report)
github.com (Report)

Other advisories for this package

fastnetmon has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-306: Missing Authentication for Critical Function) in other software:

CVE-2026-48692 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-05-26
Updated 2026-08-20
Modified 2026-06-15
Fix URL N/A

Affected Packages

Software From version Fixed in
fastnetmon — —

Similar Threats

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