Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software for…
Priority LOW 35CWE-404Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-404.
Summary
A vulnerability in the TLS 1.3 implementation for a specific cipher for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software for Cisco Firepower 3100 and 4200 Series devices could allow an authenticated, remote attacker to consume resources that are associated with incoming TLS 1.3 connections, which eventually could cause the device to stop accepting any new SSL/TLS or VPN requests. This vulnerability is due to the implementation of the TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. An attacker could exploit this vulnerability by sending a large number of TLS 1.3 connections with the specific TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. A successful exploit could allow the attacker to cause a denial of service (DoS) condition where no new incoming encrypted connections are accepted. The device must be reloaded to clear this condition. Note: These incoming TLS 1.3 connections include both data traffic and user-management traffic. After the device is in the vulnerable state, no new encrypted connections can be accepted.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00693 53rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Cisco | Cisco Adaptive Security Appliance (ASA) Software | 9.20.1; 9.20.1.5; 9.20.2; 9.20.2.10; 9.20.2.21; 9.20.2.22; 9.20.3; 9.22.1.1; 9.20.3.4; 9.20.3.7 | — | No fix listed | CNA |
| Cisco | Cisco Firepower Threat Defense Software | 7.4.0; 7.4.1; 7.4.1.1; 7.4.2; 7.6.0; 7.4.2.1 | — | No fix listed | CNA |
- Cisco Adaptive Security Appliance (ASA) Software VendorCisco Affected 9.20.1; 9.20.1.5; 9.20.2; 9.20.2.10; 9.20.2.21; 9.20.2.22; 9.20.3; 9.22.1.1; 9.20.3.4; 9.20.3.7 Fixed in — No fix listed CNA
- Cisco Firepower Threat Defense Software VendorCisco Affected 7.4.0; 7.4.1; 7.4.1.1; 7.4.2; 7.6.0; 7.4.2.1 Fixed in — No fix listed CNA
CPE configurations NVD · 24
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.0:*:*:*:*:*:*:* | 7.4.0 | Vulnerable | Cisco |
| cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.1:*:*:*:*:*:*:* | 7.4.1 | Vulnerable | Cisco |
| cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.1.1:*:*:*:*:*:*:* | 7.4.1.1 | Vulnerable | Cisco |
| cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.2:*:*:*:*:*:*:* | 7.4.2 | Vulnerable | Cisco |
| cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.2.1:*:*:*:*:*:*:* | 7.4.2.1 | Vulnerable | Cisco |
| cpe:2.3:a:cisco:secure_firewall_threat_defense:7.6.0:*:*:*:*:*:*:* | 7.6.0 | Vulnerable | Cisco |
| cpe:2.3:h:cisco:secure_firewall_3105:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:h:cisco:secure_firewall_3110:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:h:cisco:secure_firewall_3120:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:h:cisco:secure_firewall_3130:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
- cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.0:*:*:*:*:*:*:* Versions 7.4.0 Vulnerable ·Cisco
- cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.1:*:*:*:*:*:*:* Versions 7.4.1 Vulnerable ·Cisco
- cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.1.1:*:*:*:*:*:*:* Versions 7.4.1.1 Vulnerable ·Cisco
- cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.2:*:*:*:*:*:*:* Versions 7.4.2 Vulnerable ·Cisco
- cpe:2.3:a:cisco:secure_firewall_threat_defense:7.4.2.1:*:*:*:*:*:*:* Versions 7.4.2.1 Vulnerable ·Cisco
- cpe:2.3:a:cisco:secure_firewall_threat_defense:7.6.0:*:*:*:*:*:*:* Versions 7.6.0 Vulnerable ·Cisco
- cpe:2.3:h:cisco:secure_firewall_3105:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:h:cisco:secure_firewall_3110:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:h:cisco:secure_firewall_3120:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:h:cisco:secure_firewall_3130:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
Show 14 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:h:cisco:secure_firewall_3140:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:h:cisco:secure_firewall_4215:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:h:cisco:secure_firewall_4225:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:h:cisco:secure_firewall_4245:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1:*:*:*:*:*:*:* | 9.20.1 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1.5:*:*:*:*:*:*:* | 9.20.1.5 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2:*:*:*:*:*:*:* | 9.20.2 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.10:*:*:*:*:*:*:* | 9.20.2.10 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.21:*:*:*:*:*:*:* | 9.20.2.21 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.22:*:*:*:*:*:*:* | 9.20.2.22 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3:*:*:*:*:*:*:* | 9.20.3 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.4:*:*:*:*:*:*:* | 9.20.3.4 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.7:*:*:*:*:*:*:* | 9.20.3.7 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.1.1:*:*:*:*:*:*:* | 9.22.1.1 | Vulnerable | Cisco |
- cpe:2.3:h:cisco:secure_firewall_3140:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:h:cisco:secure_firewall_4215:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:h:cisco:secure_firewall_4225:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:h:cisco:secure_firewall_4245:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1:*:*:*:*:*:*:* Versions 9.20.1 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1.5:*:*:*:*:*:*:* Versions 9.20.1.5 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2:*:*:*:*:*:*:* Versions 9.20.2 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.10:*:*:*:*:*:*:* Versions 9.20.2.10 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.21:*:*:*:*:*:*:* Versions 9.20.2.21 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.22:*:*:*:*:*:*:* Versions 9.20.2.22 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3:*:*:*:*:*:*:* Versions 9.20.3 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.4:*:*:*:*:*:*:* Versions 9.20.3.4 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.7:*:*:*:*:*:*:* Versions 9.20.3.7 Vulnerable ·Cisco
- cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.1.1:*:*:*:*:*:*:* Versions 9.22.1.1 Vulnerable ·Cisco
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2025-20127
- 2026-10-03 Alias added: GHSA-pgh5-2r5j-h8rf
- 2026-10-04 EPSS moved to the 50th–90th percentile
References
Advisory 1
More Cisco Adaptive Security Appliance Software vulnerabilities
- TI-2025-14628 Buffer overflow in Cisco Secure Firewall Adaptive Security Appliance Software KEVCVSS 3.1CRITICAL 9.9
- TI-2016-05454 Buffer overflow in Cisco Adaptive Security Appliance (ASA) Software through 9.4.2.3 on… KEVCVSS 3.1HIGH 8.8
- TI-2023-06973 Authentication bypass in Cisco Adaptive Security Appliance Software KEVCVSS 3.1CRITICAL 9.1
- TI-2026-82192 Denial of service in Cisco Secure Firewall ASA and FTD SSL VPN KEVCVSS 3.1HIGH 8.6
- TI-2026-16533 Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense… KEVCVSS 3.1HIGH 8.6
- TI-2025-14657 Missing authorization in Cisco Secure Firewall Adaptive Security Appliance Software KEVCVSS 3.1HIGH 8.6
Sources
- CVE-2025-20127 · CVE Program
- CVE-2025-20127 · NVD
- FIRST EPSS
- GHSA-pgh5-2r5j-h8rf · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences