CVE-2023-20071 [Medium] | Security Bypass in Firepower Threat Defense

Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. This vulnerability is due to a flaw in the FTP module of the Snort detection engine. An attacker could exploit this vulnerability by sending crafted FTP traffic through an affected device. A successful exploit could allow the attacker to bypass FTP inspection and deliver a malicious payload.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.05%	0.52%	+0.47%
2	2025-11-21	0.14%	0.05%	-0.09%
3	2025-11-18	—	0.14%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.05%

0.52%

+0.47%

2025-11-21

0.14%

0.05%

-0.09%

2025-11-18

—

0.14%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.8	3.1	MEDIUM	`CVSS:3.1/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]
5.8	3.1	MEDIUM	`CVSS:3.1/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]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.8

3.1

MEDIUM

CVSS:3.1/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]

5.8

3.1

MEDIUM

CVSS:3.1/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]

Affected software / configurations for CVE-2023-20071

Vendor	Product	Version	Raw CPE
cisco	firepower_threat_defense	< 6.4.0.17	cpe:2.3:a:cisco:firepower_threat_defense::::::::
cisco	firepower_threat_defense	>= 6.5.0, < 7.0.6	cpe:2.3:a:cisco:firepower_threat_defense::::::::
cisco	firepower_threat_defense	>= 7.1.0, < 7.2.4	cpe:2.3:a:cisco:firepower_threat_defense::::::::
cisco	firepower_threat_defense	>= 7.3.0, < 7.3.1.2	cpe:2.3:a:cisco:firepower_threat_defense::::::::
cisco	firepower_threat_defense	>= 6.7.0, < 7.0.5	cpe:2.3:a:cisco:firepower_threat_defense::::::::
cisco	firepower_threat_defense	>= 7.1.0, < 7.1.0.3	cpe:2.3:a:cisco:firepower_threat_defense::::::::
cisco	firepower_threat_defense	>= 7.2.0, < 7.2.1	cpe:2.3:a:cisco:firepower_threat_defense::::::::
cisco	cyber_vision	< 4.1.3	cpe:2.3:a:cisco:cyber_vision::::::::
cisco	unified_threat_defense	>= 17.3, < 17.3.8	cpe:2.3:a:cisco:unified_threat_defense::::::::
cisco	unified_threat_defense	>= 17.6, < 17.6.6	cpe:2.3:a:cisco:unified_threat_defense::::::::
cisco	unified_threat_defense	>= 17.9, < 17.9.4	cpe:2.3:a:cisco:unified_threat_defense::::::::
cisco	unified_threat_defense	>= 17.11, < 17.11.1a	cpe:2.3:a:cisco:unified_threat_defense::::::::
cisco	unified_threat_defense	>= 17.12, < 17.12.1a	cpe:2.3:a:cisco:unified_threat_defense::::::::
cisco	meraki_mx_security_appliance_firmware	—	cpe:2.3:o:cisco:meraki_mx_security_appliance_firmware:-:::::::*

References for CVE-2023-20071

URL	Tags
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-ftd-zXYtnjOM	Vendor Advisory

URL

CVE-2023-20071

Exploit prediction scoring system (EPSS) score for CVE-2023-20071

Common vulnerability scoring system (CVSS) metrics for CVE-2023-20071

Weakness enumeration for CVE-2023-20071

Affected software / configurations for CVE-2023-20071

References for CVE-2023-20071