Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SSL/TLS Session Denial of Service Vulnerability
Published Oct 21, 2020
8.6
HIGHCVSS 3.1
EPSS 1.78%
Description
A vulnerability in the SSL/TLS session handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory leak when closing SSL/TLS connections in a specific state. An attacker could exploit this vulnerability by establishing several SSL/TLS sessions and ensuring they are closed under certain conditions. A successful exploit could allow the attacker to exhaust memory resources in the affected device, which would prevent it from processing new SSL/TLS connections, resulting in a DoS. 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 |
|
- < 9.6
- < 6.3.0.6
- ≥ 6.4.0 · < 6.4.0.10
- ≥ 6.5.0 · < 6.6.1
- ≥ 9.8.0 · < 9.8.4.26
- ≥ 9.9.0 · < 9.9.2.80
- ≥ 9.10.0 · < 9.10.1.44
- ≥ 9.12.0 · < 9.12.4.4
- ≥ 9.13.0 · < 9.13.1.13
- ≥ 9.14.0 · < 9.14.1.19
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
No CVSS v3.0 score for this CVE.
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 13, 2024 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (14 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 1.78% (0.01778) | 77.47th | v5 (v2026.06.15) |
| Jun 15, 2026 | 1.74% (0.01742) | 74.73th | v5 (v2026.06.15) |
| Mar 17, 2025 | 1.86% (0.01858) | 81.85th | v4 (v2025.03.14) |
| Jul 20, 2024 | 0.16% (0.00160) | 52.99th | v3 (v2023.03.01) |
| Jul 7, 2023 | 0.16% (0.00160) | 51.60th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.14% (0.00138) | 47.55th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.05% (0.01055) | 52.13th | v2 (v2022.01.01) |
| Sep 17, 2022 | 1.05% (0.01055) | 50.47th | 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 | v1 |
| 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-ftd-tcp-dos-N3DMnU4T vendor-advisoryx_refsource_CISCOVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-tcp-dos-N3DMnU4T | vendor-advisoryx_refsource_CISCOVendor Advisory |
Change history (0)
No recorded changes yet.