CVE-2019-1980 | Cisco Firepower Threat Defense Software Nonstandard Protocol Detection Bypass Vulnerability

A vulnerability in the protocol detection component of Cisco Firepower Threat Defense Software, Cisco FirePOWER Services Software for ASA, and Cisco Firepower Management Center Software could allow an unauthenticated, remote attacker to bypass filtering protections. The vulnerability is due to improper detection of the initial use of a protocol on a nonstandard port. An attacker could exploit this vulnerability by sending traffic on a nonstandard port for the protocol in use through an affected device. An exploit could allow the attacker to bypass filtering and deliver malicious requests to protected systems that would otherwise be blocked. Once the initial protocol flow on the nonstandard port is detected, future flows on the nonstandard port will be successfully detected and handled as configured by the applied policy.

Published: 2019-11-05 Last update: 2024-11-26 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2019-1980 is rated Low Risk (38.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.29%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2019-1980

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-19 0.25% 0.29% +0.04%
2 2025-03-17 0.13% 0.25% +0.12%
3 2023-03-07 0.13%

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-1980

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 1.4 [email protected]
5.8 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
10.0 2.9 [email protected]

Weakness enumeration for CVE-2019-1980

Affected software / configurations for CVE-2019-1980

Vendor Product Version Raw CPE
cisco firepower_services_software_for_asa cpe:2.3:a:cisco:firepower_services_software_for_asa:*:*:*:*:*:*:*:*
cisco firepower_threat_defense cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
cisco secure_firewall_management_center >= 2.9.12, <= 2.9.12.15 cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
cisco secure_firewall_management_center >= 2.9.13, <= 2.9.13.6 cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
cisco secure_firewall_management_center >= 2.9.14.0, <= 2.9.14.5 cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
cisco secure_firewall_management_center 2.9.15 cpe:2.3:a:cisco:secure_firewall_management_center:2.9.15:*:*:*:*:*:*:*
cisco secure_firewall_management_center 2.9.16 cpe:2.3:a:cisco:secure_firewall_management_center:2.9.16:*:*:*:*:*:*:*

References for CVE-2019-1980

cvelogic Threat Intelligence