Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SSL/TLS Denial of Service Vulnerability
Published May 6, 2020
8.6
HIGHCVSS 3.1
EPSS 1.92%
Description
A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust memory resources on the affected device, leading to a denial of service (DoS) condition. The vulnerability is due to improper resource management for inbound SSL/TLS connections. An attacker could exploit this vulnerability by establishing multiple SSL/TLS connections with specific conditions to the affected device. A successful exploit could allow the attacker to exhaust the memory on the affected device, causing the device to stop accepting new SSL/TLS connections and resulting in a DoS condition for services on the device that process SSL/TLS traffic. Manual intervention is required to recover an affected device.
Affected products
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||
|---|---|---|---|---|---|---|
| Cisco | Cisco Adaptive Security Appliance (ASA) Software | n/a |
|
Configuration 1
- ≥ 6.2.3 · < 6.2.3.16
- ≥ 6.3.0 · < 6.3.0.6
- ≥ 6.4.0 · < 6.4.0.9
- ≥ 6.5.0 · < 6.5.0.5
Configuration 2
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Configuration 3
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Configuration 4
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Running on/with
- n/a
Configuration 5
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Running on/with
- n/a
Configuration 6
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Configuration 7
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Running on/with
- n/a
Configuration 8
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Configuration 9
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Running on/with
- n/a
Configuration 10
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Configuration 11
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Running on/with
- n/a
Configuration 12
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Configuration 13
- 9.4\(4\)
- 9.8\(4.18\)
- 100.13\(0\)
Running on/with
- n/a
Configuration 14
- ≥ 9.6 · < 9.6.4.40
- ≥ 9.8 · < 9.8.4.20
- ≥ 9.9 · < 9.9.2.66
- ≥ 9.10 · < 9.10.1.37
- ≥ 9.12 · < 9.12.3.2
- ≥ 9.13 · < 9.13.1.7
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
AV:N/AC:L/Au:N/C:N/I:N/A:P
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed Nov 15, 2024 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Table of values (13 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 1.92% (0.01920) | 79.18th | v5 (v2026.06.15) |
| Jun 15, 2026 | 2.13% (0.02128) | 79.47th | v5 (v2026.06.15) |
| Mar 19, 2025 | 1.86% (0.01858) | 81.12th | v4 (v2025.03.14) |
| Jul 20, 2024 | 0.16% (0.00160) | 52.99th | v3 (v2023.03.01) |
| Jun 26, 2024 | 0.16% (0.00160) | 52.79th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.16% (0.00160) | 50.78th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.05% (0.01055) | 52.13th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.05% (0.01055) | 48.43th | v2 (v2022.01.01) |
| Feb 4, 2022 | 4.50% (0.04499) | 74.08th | v2 (v2022.01.01) |
| Feb 3, 2022 | 2.86% (0.02857) | 63.60th | v5 (v2026.06.15) |
| Jan 6, 2022 | 2.86% (0.02857) | 63.25th | v1 |
| Sep 1, 2021 | 0.65% (0.00651) | 45.91th | v1 |
| Apr 14, 2021 | 0.65% (0.00651) | 0.00th | v1 |
References (1)
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-vpn-dos-qY7BHpjN vendor-advisoryx_refsource_CISCOVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-vpn-dos-qY7BHpjN | vendor-advisoryx_refsource_CISCOVendor Advisory |
Change history (0)
No recorded changes yet.