CVE-2026-20340

high
Assigned by CNA: cisco
Published 2026-09-16 · Modified 2026-09-16
CVSS v3
8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4 NEW
not yet in upstream
VIR risk
8.8

Description

A vulnerability in Cisco Secure FMC Software could allow an authenticated, remote attacker to execute arbitrary commands at the root privilege level. This vulnerability is due to unsecured deserialization of web-management user-controlled data. An attacker could exploit this vulnerability by authenticating to the device and sending a crafted HTTP payload. A successful exploit could allow the attacker to save the crafted payload and then execute it on the underlying operating system as root. To exploit this vulnerability, the attacker must have valid credentials for a user account with at least the role of Security Analyst (read-only).

Predictions

Exploit likelihood
92%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

References

CWEs

CWE-502

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.