{"id":"CVE-2026-48693","aliases":["DEBIAN-CVE-2026-48693","EUVD-2026-31899","GHSA-f762-5mrw-32x8","UBUNTU-CVE-2026-48693"],"status":"published","title":"FastNetMon Community Edition through 1.2.9 is vulnerable to a local symlink attack via...","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).","severity":{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.00127,"percentile":0.02348,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-59"],"published":"2026-05-26T00:00:00Z","modified":"2026-10-28T02:31:14Z","affected":[{"source":"osv","ecosystem":"Debian:12","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.4-2","1.2.4-2+deb12u1","1.2.5-1","1.2.5-2","1.2.5-2~bpo12+1","1.2.6-1","1.2.6-1~bpo12+1","1.2.7-1","1.2.7-1~bpo12+1","1.2.8+git20250911-1","1.2.8+git20250911-2","1.2.8-1","1.2.8-1~bpo12+1","1.2.9-1"]},{"source":"osv","ecosystem":"Debian:13","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-2","1.2.8-1","1.2.9-0+deb13u1","1.2.9-1"]},{"source":"osv","ecosystem":"Debian:14","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-2","1.2.8-1","1.2.9-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.3+dfsg-3","1.1.3+dfsg-4","1.1.3+dfsg-6build1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.4-1","1.1.4-1build3","1.1.4-1build4","1.1.4-1build5","1.1.4-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.5-1","1.2.6-1","1.2.6-1build1","1.2.6-1build2","1.2.6-1build3","1.2.6-1build4","1.2.6-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8-1build1","1.2.8-1build2","1.2.8+git20250911-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8+git20250911-2","1.2.9-1","1.2.9-1build1","1.2.9-1build2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:26.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-1build1","1.2.8+git20250911-1build2","1.2.8+git20250911-2","1.2.8+git20250911-2ubuntu0.1~esm1"]}],"products":[{"vendor":"pavel-odintsov","product":"fastnetmon"}],"references":[{"url":"https://github.com/pavel-odintsov/fastnetmon","tags":["Product","package","report"]},{"url":"https://github.com/pavel-odintsov/fastnetmon/blob/master/src/fastnetmon.cpp","tags":["Product","web","report"]},{"url":"https://github.com/pavel-odintsov/fastnetmon/blob/master/src/fastnetmon_logic.cpp","tags":["Product","web","report"]},{"url":"https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48693-symlink-tmp","tags":["Third Party Advisory","article","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48693","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-f762-5mrw-32x8"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48693.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-48693","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-48693","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-48693","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-48693","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).","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-05-26T20:33:37.827Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"adp"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T14:19:47.998488Z"}],"euvd":[{"id":"EUVD-2026-31899","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).","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-05-26T20:33:37Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T18:21:06.423934Z"}],"ghsa":[{"id":"GHSA-f762-5mrw-32x8","title":"FastNetMon Community Edition through 1.2.9 is vulnerable to a local symlink attack via...","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).","status":"published","published":"2026-05-26T18:31:47Z","modified":"2026-05-26T21:31:58Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T15:08:18.762226Z"}],"nvd":[{"id":"CVE-2026-48693","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).","status":"published","published":"2026-05-26T17:16:53.807Z","modified":"2026-07-24T11:10:00.17Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"primary"},{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T14:12:20.511562Z"}],"osv":[{"id":"CVE-2026-48693","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).","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-10-28T02:31:14.537568226Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:06.701612Z"},{"id":"DEBIAN-CVE-2026-48693","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).","status":"published","published":"2026-05-26T17:16:53.807Z","modified":"2026-10-01T03:03:16.524371628Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:56.444225Z"},{"id":"UBUNTU-CVE-2026-48693","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).","status":"published","published":"2026-05-26T17:16:00Z","modified":"2026-10-17T12:58:31.128720746Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium"},{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T16:56:33.391918Z"}]}}