CVE-2020-3555 json
Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SIP Denial of Service Vulnerability
published 6y ago modified 2mo ago also EUVD-2020-24826
- cvss
- 6.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.7%
- EPSS 1.7% chance of exploitation in 30 days, percentile 77%
- public exploits
- 0
- none known
Summary
A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. An attacker could exploit this vulnerability by sending a high rate of crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a watchdog timeout and crash, resulting in a crash and reload of the affected device.
Patch / fix
- cisco adaptive_security_appliance 9.6.4.43
- cisco secure_firewall_threat_defense 6.3.0.6, 6.4.0.10, 6.5.0.5
- cisco adaptive_security_appliance_software 9.8.4.24, 9.9.2.80, 9.10.1.43, 9.12.4.2, 9.13.1.13, 9.14.1.19
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- last yr.
Exploit prediction
1.70% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 7.8 | AV:N/AC:L/Au:N/C:N/I:N/A:C |
Affected products
- Cisco Cisco Adaptive Security Appliance (ASA) Software
Classification
- Weakness
-
- CWE-404 Improper Resource Shutdown or Release
References
Sources
- CVE List CVE-2020-3555
- NVD CVE-2020-3555
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