CVE-2026-20018
MEDIUMDescription
A vulnerability in the sftunnel functionality of Cisco Secure Firewall Management Center (FMC) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with administrative privileges to write arbitrary files as root on the underlying operating system. This vulnerability is due to insufficient validation of the directory path during file synchronization. An attacker could exploit this vulnerability by crafting a directory path outside of the expected file location. A successful exploit could allow the attacker to create or replace any file on the underlying operating system.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 35% of all known CVEs.
References
Related Vulnerabilities
Other CWE-27 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-23897 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2024-24809 | High | 8.5 | 54% | - | - |
| CVE-2023-34125 | Medium | 6.5 | 25% | - | Fix |
| CVE-2022-24785 | High | 7.5 | 5.5% | - | Fix |
| CVE-2023-50254 | Critical | 9.3 | 2.1% | - | Fix |
| CVE-2021-35027 | High | 7.5 | 2.0% | - | - |
Common questions
How do I fix CVE-2026-20018?
No published fix for CVE-2026-20018 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-20018 being actively exploited?
Not that we know of. CVE-2026-20018 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.42% is the estimated probability that it will be exploited in the next 30 days. That is higher than 35% of all scored CVEs.
How severe is CVE-2026-20018?
CVE-2026-20018 has a CVSS v3 base score of 5.9, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-05.