CVE-2026-48693 Affecting fastnetmon package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.13% (3rd percentile)

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  • Snyk IDSNYK-DEBIAN14-FASTNETMON-17089117
  • published29 May 2026
  • disclosed26 May 2026

Introduced: 26 May 2026

CVE-2026-48693  (opens in a new tab)

How to fix?

There is no fixed version for Debian:14 fastnetmon.

NVD Description

Note: Versions mentioned in the description apply only to the upstream fastnetmon package and not the fastnetmon package as distributed by Debian. See How to fix? for Debian:14 relevant fixed versions and status.

FastNetMon Community Edition through 1.2.9 is vulnerable to a local symlink attack via predictable file paths in /tmp. The statistics file path defaults to '/tmp/fastnetmon.dat' (src/fastnetmon.cpp line 159). The print_screen_contents_into_file() function (src/fastnetmon_logic.cpp line 2186) opens this path with std::ios::trunc without checking for symlinks or using O_NOFOLLOW. Additionally, the chmod() call on line 2190 always operates on cli_stats_file_path regardless of which file_path parameter was passed (a bug that applies wrong permissions), and the umask is set to 0 during daemonization (src/fastnetmon.cpp line 1821), making all created files world-writable. A local attacker can exploit this to overwrite arbitrary files as the FastNetMon process user (typically root).

CVSS Base Scores

version 3.1