CVE-2021-40117
No exploitation reported by the sources we read.
- Published2021-10-27
- Fixed in7.0.1 · 6.7.0.3 · 6.6.5 · 6.4.0.13 · 6.2.3.17
- WeaknessCWE-119 · CWE-400
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
A vulnerability in SSL/TLS message handler for 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. This vulnerability exists because incoming SSL/TLS packets are not properly processed. An attacker could exploit this vulnerability by sending a crafted SSL/TLS packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
Timeline
dates in UTC- 2021-10-2719:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-40117?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-40117?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 7.0 | ≥ 7.0.0, < 7.0.1 | 7.0.1 | NVD |
| 6.7 | ≥ 6.7.0, < 6.7.0.3 | 6.7.0.3 | NVD |
| 6.x | ≥ 6.5.0, < 6.6.5 | 6.6.5 | NVD |
| 6.x | ≥ 6.3.0, < 6.4.0.13 | 6.4.0.13 | NVD |
| 6.2 | < 6.2.3.17 | 6.2.3.17 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 9.16 | ≥ 9.16.0, < 9.16.2.3 | 9.16.2.3 | NVD |
| 9.15 | ≥ 9.15.0, < 9.15.1.17 | 9.15.1.17 | NVD |
| 9.x | ≥ 9.13.0, < 9.14.3.9 | 9.14.3.9 | NVD |
| 9.x | ≥ 9.9.0, < 9.12.4.26 | 9.12.4.26 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 9.9 | = 009.009\(002.085\) | no fix published | NVD |
| 9.14 | = 009.014\(002.106\) | no fix published | NVD |
8 more products in the sources.
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Cisco secure firewall threat defense to 7.0.1 · 6.7.0.3 · 6.6.5 · 6.4.0.13 · 6.2.3.17
Advisories and patches
- tools.cisco.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2021-10-27
- Last Modified
- 2026-08-11
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-40117?
Is CVE-2021-40117 actively exploited?
What is the CVSS score for CVE-2021-40117?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.