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CVE-2026-20324

critical

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, rem…

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker to execute arbitrary commands as root. This vulnerability exists because a registered sftunnel peer has incorrect permissions to write an arbitrary file to any location on the device. An attacker could exploit this vulnerability by hijacking the sftunnel communication connection or being a valid registered sftunnel peer and sending an sftunnel command to write a malicious file to the disk of an affected device. A successful exploit could allow the attacker to write a file to the device that is executed with root privileges. To exploit this vulnerability, the attacker must have valid user credentials on the affected device.

CVSS
9.9
9.9 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Severity source: NVD CVSS v3.1 (psirt@cisco.com)
Timeline (UTC)
Published: 2026-09-16 20:17
Modified: 2026-09-18 04:17
NVD status: Awaiting Analysis
Last synced 2 days ago
Verified against the source API 2026-10-27 06:54 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

Not reported by the source (unknown — not "none").

Weakness classification (CWE)

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:54 UTC · record ↗

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