TI-2021-17320 Aliases CVE-2021-40125 GHSA-cg2g-27wj-x8x6

Use after free in Cisco Adaptive Security Appliance Software

LOW 31CWE-416Published 2021-10-27 · Updated 2024-11-07

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 · NVD. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.

Summary

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device. This vulnerability is due to improper control of a resource. An attacker with the ability to spoof a trusted IKEv2 site-to-site VPN peer and in possession of valid IKEv2 credentials for that peer could exploit this vulnerability by sending malformed, authenticated IKEv2 messages to an affected device. A successful exploit could allow the attacker to trigger a reload of the device.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.01024 63rd 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	all versions	—	No fix listed	CNA

Cisco Adaptive Security Appliance (ASA) Software VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 18

CPE	Versions	Role	Vendor
cpe:2.3:a:cisco:secure_firewall_threat_defense::::::::	before 6.4.0.13; 6.6.0 to before 6.6.5; 6.7.0 to before 6.7.0.3; 7.0.0 to before 7.0.1	Vulnerable	Cisco
cpe:2.3:o:cisco:adaptive_security_appliance_software::::::::	9.8.0 to before 9.8.4.40; 9.9.0 to before 9.12.4.30; 9.14.0 to before 9.14.3.9; 9.15.0 to before 9.15.1.17; 9.16.0 to before 9.16.2	Vulnerable	Cisco
cpe:2.3:o:cisco:asa_5512-x_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5512-x:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:o:cisco:asa_5505_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5505:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:o:cisco:asa_5515-x_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5515-x:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:o:cisco:asa_5525-x_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5525-x:-:::::::*	not specified by NVD	Running on	Cisco

cpe:2.3:a:cisco:secure_firewall_threat_defense:*:*:*:*:*:*:*:* Versions before 6.4.0.13; 6.6.0 to before 6.6.5; 6.7.0 to before 6.7.0.3; 7.0.0 to before 7.0.1 Vulnerable ·Cisco
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* Versions 9.8.0 to before 9.8.4.40; 9.9.0 to before 9.12.4.30; 9.14.0 to before 9.14.3.9; 9.15.0 to before 9.15.1.17; 9.16.0 to before 9.16.2 Vulnerable ·Cisco
cpe:2.3:o:cisco:asa_5512-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5512-x:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:o:cisco:asa_5505_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5505:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:o:cisco:asa_5515-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5515-x:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:o:cisco:asa_5525-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5525-x:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco

Show 8 more CPE

CPE	Versions	Role	Vendor
cpe:2.3:o:cisco:asa_5545-x_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5545-x:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:o:cisco:asa_5555-x_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5555-x:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:o:cisco:asa_5580_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5580:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:o:cisco:asa_5585-x_firmware:009.016\(001.025\):::::::*	009.016(001.025)	Vulnerable	Cisco
cpe:2.3:h:cisco:asa_5585-x:-:::::::*	not specified by NVD	Running on	Cisco

cpe:2.3:o:cisco:asa_5545-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5545-x:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:o:cisco:asa_5555-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5555-x:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:o:cisco:asa_5580_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5580:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:o:cisco:asa_5585-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* Versions 009.016(001.025) Vulnerable ·Cisco
cpe:2.3:h:cisco:asa_5585-x:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-40125
2026-10-03 Alias added: GHSA-cg2g-27wj-x8x6

References

Advisory 1

20211027 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IKEv2 Site-to-Site VPN Denial of Service Vulnerability

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

See all 354 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences