9.1

CVE-2026-20341: cisco cisco secure firewall management center (fmc) Deserialization of Untrusted Data

CVSS: 9.1v3.1CriticalAwaiting analysis
Published 16-09-2026Last modified 18-09-2026
Open JSON

Vulnerability summary

CVE-2026-20341 is a critical (CVSS 9.1) Deserialization of Untrusted Data vulnerability in cisco cisco secure firewall management center (fmc). EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 37.6% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.45%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 16-09-2026
    PublishedVulnerability first disclosed.
  2. 18-09-2026
    Last modifiedVulnerability information updated.

Description

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges. This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer. To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.45%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

0.00 pp

From 0.45% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.45%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cisco1 product
  • cisco secure firewall management center (fmc)7.0.0 | 7.0.0.1 | 7.0.1 | 7.0.1.1 | 7.0.2 | 7.2.0 | 7.0.2.1 | 7.0.3 | 7.2.0.1 | 7.0.4 | 7.2.1 | 7.0.5 | 7.3.0 | 7.2.2 | 7.3.1 | 7.2.3 | 7.2.3.1 | 7.2.4 | 7.0.6 | 7.2.4.1 | 7.2.5 | 7.3.1.1 | 7.4.0 | 7.0.6.1 | 7.2.5.1 | 7.4.1 | 7.2.6 | 7.4.1.1 | 7.0.6.2 | 7.2.7 | 7.2.5.2 | 7.3.1.2 | 7.2.8 | 7.6.0 | 7.4.2 | 7.2.8.1 | 7.0.6.3 | 7.4.2.1 | 7.2.9 | 7.0.7 | 7.7.0 | 7.4.2.2 | 7.2.10 | 7.6.1 | 7.4.2.3 | 7.0.8 | 7.6.2 | 7.7.10 | 7.2.10.1 | 7.0.8.1 | 7.6.2.1 | 7.2.10.2 | 7.7.10.1 | 7.4.2.4 | 7.4.3 | 7.6.3 | 7.7.11 | 7.6.4 | 10.0.0 | 7.4.4 | 7.4.5 | 7.0.9 | 7.2.11 | 7.7.12 | 7.6.5 | 7.4.6 | 10.0.1 | 7.4.7

1 vendor · 1 product

References

1 links