How severe is CVE-2026-48693?

CVE-2026-48693 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-48693 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-48693?

CVE-2026-48693 affects Pavel-odintsov Fastnetmon. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-48693?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-48693 have an EU (EUVD) identifier?

Yes. CVE-2026-48693 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31899.

When was CVE-2026-48693 published?

CVE-2026-48693 was published on 2026-05-26 and last updated on 2026-06-17.

CVE-2026-48693

CVE-2026-48693 is a medium-severity vulnerability in Pavel-odintsov Fastnetmon with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-59.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31899
Weakness: CWE-59
Affected product: Pavel-odintsov Fastnetmon
Published: 2026-05-26
Last modified: 2026-06-17

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).

Frequently asked questions

What is CVE-2026-48693?: 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).
How severe is CVE-2026-48693?: CVE-2026-48693 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-48693 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-48693?: CVE-2026-48693 affects Pavel-odintsov Fastnetmon. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-48693?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-48693 have an EU (EUVD) identifier?: Yes. CVE-2026-48693 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31899.
When was CVE-2026-48693 published?: CVE-2026-48693 was published on 2026-05-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:pavel-odintsov:fastnetmon:*:*:*:*:community:*:*:*

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