CVE-2026-48693FastNetMon Community Edition through 1.2.9 is vulnerable to a local symlink attack via predictable file paths in /tmp.
Updated under an hour ago ()
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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
- 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
- Weakness (CWE)
- CWE-59
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jul 24, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
pavel-odintsov fastnetmon pavel-odintsov:fastnetmon | through 1.2.9 | NVD |
References
- https://github.com/pavel-odintsov/fastnetmonproduct
- https://github.com/pavel-odintsov/fastnetmon/blob/master/src/fastnetmon.cppproduct
- https://github.com/pavel-odintsov/fastnetmon/blob/master/src/fastnetmon_logic.cppproduct
- https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48693-symlink-tmpthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.