How severe is CVE-2020-3456?

CVE-2020-3456 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-3456 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3456?

CVE-2020-3456 affects Cisco Firepower Extensible Operating System. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-3456?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-3456 published?

CVE-2020-3456 was published on 2020-10-21 and last updated on 2026-06-17.

CVE-2020-3456

CVE-2020-3456 is a high-severity vulnerability in Cisco Firepower Extensible Operating System with a CVSS 3.x base score of 8.8. 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-352.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-352
Affected product: Cisco Firepower Extensible Operating System
Published: 2020-10-21
Last modified: 2026-06-17

Description

A vulnerability in the Cisco Firepower Chassis Manager (FCM) of Cisco FXOS Software could allow an unauthenticated, remote attacker to conduct a cross-site request forgery (CSRF) attack against a user of an affected device. The vulnerability is due to insufficient CSRF protections for the FCM interface. An attacker could exploit this vulnerability by persuading a targeted user to click a malicious link. A successful exploit could allow the attacker to send arbitrary requests that could take unauthorized actions on behalf of the targeted user.

Frequently asked questions

What is CVE-2020-3456?: A vulnerability in the Cisco Firepower Chassis Manager (FCM) of Cisco FXOS Software could allow an unauthenticated, remote attacker to conduct a cross-site request forgery (CSRF) attack against a user of an affected device. The vulnerability is due to insufficient CSRF protections for the FCM interface. An attacker could exploit this vulnerability by persuading a targeted user to click a malicious link. A successful exploit could allow the attacker to send arbitrary requests that could take unauthorized actions on behalf of the targeted user.
How severe is CVE-2020-3456?: CVE-2020-3456 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-3456 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3456?: CVE-2020-3456 affects Cisco Firepower Extensible Operating System. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-3456?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-3456 published?: CVE-2020-3456 was published on 2020-10-21 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fxosfcm-csrf-uhO4e5BZ

Affected products (1)

cpe:2.3:o:cisco:firepower_extensible_operating_system:2.4\(1.249\):*:*:*:*:*:*:*

More vulnerabilities in Cisco Firepower Extensible Operating System

CVE-2018-0310 — Critical (CVSS 9.8): A vulnerability in the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software could allow an…
CVE-2015-6435 — Critical (CVSS 9.8): An unspecified CGI script in Cisco FX-OS before 1.1.2 on Firepower 9000 devices and Cisco Unified Computing System…
CVE-2021-1368 — High (CVSS 8.8): A vulnerability in the Unidirectional Link Detection (UDLD) feature of Cisco FXOS Software and Cisco NX-OS Software…
CVE-2020-3172 — High (CVSS 8.8): A vulnerability in the Cisco Discovery Protocol feature of Cisco FXOS Software and Cisco NX-OS Software could allow an…
CVE-2018-0395 — High (CVSS 8.8): A vulnerability in the Link Layer Discovery Protocol (LLDP) implementation for Cisco FXOS Software and Cisco NX-OS…
CVE-2018-0303 — High (CVSS 8.8): A vulnerability in the Cisco Discovery Protocol component of Cisco FXOS Software and Cisco NX-OS Software could allow…

All CVEs affecting Cisco Firepower Extensible Operating System →

Other CWE-352 (Cross-Site Request Forgery (CSRF)) vulnerabilities

CVE-2025-32642 — Critical (CVSS 10.0): Cross-Site Request Forgery (CSRF) vulnerability in appsbd Vite Coupon vite-coupon allows Remote Code Inclusion.This…
CVE-2025-23922 — Critical (CVSS 10.0): Cross-Site Request Forgery (CSRF) vulnerability in Harsh iSpring Embedder embed-ispring allows Upload a Web Shell to a…
CVE-2017-5145 — Critical (CVSS 10.0): An issue was discovered in Carlo Gavazzi VMU-C EM prior to firmware Version A11_U05, and VMU-C PV prior to firmware…
CVE-2019-25729 — Critical (CVSS 9.8): PDF Signer 3.0 contains a server-side template injection vulnerability that allows unauthenticated attackers to execute…
CVE-2025-48340 — Critical (CVSS 9.8): Cross-Site Request Forgery (CSRF) vulnerability in Danny Vink User Profile Meta Manager user-profile-meta allows…
CVE-2025-2907 — Critical (CVSS 9.8): The Order Delivery Date WordPress plugin before 12.3.1 does not have authorization and CSRF checks when importing…

Browse all CWE-352 (Cross-Site Request Forgery (CSRF)) vulnerabilities →