Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Resource Exhaustion Denial of Service Vulnerability
A vulnerability in the memory management of Cisco Adaptive Security Appliance (ASA) Software and 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 is due to improper resource management when connection rates are high. An attacker could exploit this vulnerability by opening a significant number of connections on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Oct 27, 2021
- Updated
- Aug 11, 2026
- EPSS
- 1.4% · 72th percentile
- CWE
- CWE-400
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.4%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.5
- CNA · cisco
- 8.6
- 1.1 point gap
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | secure firewall threat defense | cpe:2.3:a:cisco:secure_firewall_threat_defense |
| cisco | adaptive security appliance software | cpe:2.3:o:cisco:adaptive_security_appliance_software |
| cisco | asa 5512-x firmware | cpe:2.3:o:cisco:asa_5512-x_firmware |
| cisco | asa 5512-x | cpe:2.3:h:cisco:asa_5512-x |
| cisco | asa 5505 firmware | cpe:2.3:o:cisco:asa_5505_firmware |
| cisco | asa 5505 | cpe:2.3:h:cisco:asa_5505 |
| cisco | asa 5515-x firmware | cpe:2.3:o:cisco:asa_5515-x_firmware |
| cisco | asa 5515-x | cpe:2.3:h:cisco:asa_5515-x |
| cisco | asa 5525-x firmware | cpe:2.3:o:cisco:asa_5525-x_firmware |
| cisco | asa 5525-x | cpe:2.3:h:cisco:asa_5525-x |
| cisco | asa 5545-x firmware | cpe:2.3:o:cisco:asa_5545-x_firmware |
| cisco | asa 5545-x | cpe:2.3:h:cisco:asa_5545-x |
and 6 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco adaptive security appliance software9.8.0 and later · before 9.8.4.40
- cisco adaptive security appliance software9.12.0 and later · before 9.12.4.29
- cisco adaptive security appliance software9.14.0 and later · before 9.14.3.9
- cisco adaptive security appliance software9.15.0 and later · before 9.15.1.17
- cisco adaptive security appliance software9.16.0 and later · before 9.16.2.3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.
Cisco Cisco Adaptive Security Appliance (ASA) Software
- n/aaffected
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2020-3259Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Information Disclosure VulnerabilityKEV82Now
- CVE-2020-3580Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Interface Cross-Site Scripting VulnerabilitiesKEV80Now
- CVE-2020-3187Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Path Traversal Vulnerability65This week
- CVE-2024-20481A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat DefeKEV58Plan
- CVE-2022-20759Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Interface Privilege Escalation Vulnerability43Plan
- CVE-2020-3562Cisco Firepower 2100 Series SSL/TLS Inspection Denial of Service Vulnerability35Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-400 · Uncontrolled Resource ConsumptionCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Root cause
Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.
The bug in code
The whole CWE-400 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
function expand(node) { return node.children.map(expand);}Fixed
const MAX_DEPTH = 32;function expand(node, depth = 0) { if (depth > MAX_DEPTH) throw new Error("too deep"); return node.children.map((c) => expand(c, depth + 1));}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.