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).
Published: 2026-05-26
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Wed, 27 May 2026 14:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:pavel-odintsov:fastnetmon:*:*:*:*:community:*:*:*

Wed, 27 May 2026 00:45:00 +0000

Type Values Removed Values Added
Title Local Symlink Attack via Predictable Temporary File in FastNetMon

Tue, 26 May 2026 23:30:00 +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 21:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-59
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


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).
References

Subscriptions

Pavel-odintsov Fastnetmon
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-05-26T20:33:37.827Z

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

Link: CVE-2026-48693

cve-icon Vulnrichment

Updated: 2026-05-26T20:31:06.082Z

cve-icon NVD

Status : Analyzed

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

Modified: 2026-06-17T10:55:11.630

Link: CVE-2026-48693

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-27T00:30:20Z

Weaknesses