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).

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History

Tue, 26 May 2026 20:00:00 +0000

Type Values Removed Values Added
First Time appeared Pavel-odintsov
Pavel-odintsov fastnetmon
Vendors & Products Pavel-odintsov
Pavel-odintsov fastnetmon

Tue, 26 May 2026 19:00:00 +0000

Type Values Removed Values Added
Title Symlink Attack Allows Root File Overwrite in FastNetMon Community Edition
Weaknesses CWE-22
CWE-284

Tue, 26 May 2026 17:00:00 +0000

Type Values Removed Values Added
Description 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).
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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-05-26T16:48:45.595Z

Reserved: 2026-05-22T00:00:00.000Z

Link: CVE-2026-48693

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-26T17:16:53.807

Modified: 2026-05-26T19:29:02.327

Link: CVE-2026-48693

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-26T19:45:06Z

Weaknesses