A vulnerability in the authentication, authorization, and accounting (AAA) implementation of Cisco Firepower Extensible Operating System (FX
A vulnerability in the authentication, authorization, and accounting (AAA) implementation of Cisco Firepower Extensible Operating System (FXOS) and NX-OS System Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability occurs because AAA processes prevent the NX-OS System Manager from receiving keepalive messages when an affected device receives a high rate of login attempts, such as in a brute-force login attack. System memory can run low on the FXOS devices under the same conditions, which could cause the AAA process to unexpectedly restart or cause the device to reload. An attacker could exploit this vulnerability by performing a brute-force login attack against a device that is configured with AAA security services. A successful exploit could allow the attacker to cause the affected device to reload. This vulnerability affects the following Cisco products if they are running Cisco FXOS or NX-OS System Software that is configured for AAA services: Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, Unified Computing System (UCS) 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCuq58760, CSCuq71257, CSCur97432, CSCus05214, CSCux54898, CSCvc33141, CSCvd36971, CSCve03660.
- Published
- Oct 19, 2017
- Updated
- Jun 16, 2026
- EPSS
- 4.5% · 91th percentile
- CWE
- CWE-770
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Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 34 / 40 · 8.6 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 4.5%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | firepower extensible operating system | cpe:2.3:o:cisco:firepower_extensible_operating_system |
| cisco | firepower 4100 | cpe:2.3:h:cisco:firepower_4100 |
| cisco | fxos | cpe:2.3:o:cisco:fxos |
| cisco | firepower 9300 | cpe:2.3:h:cisco:firepower_9300 |
| cisco | nx-os | cpe:2.3:o:cisco:nx-os |
| cisco | mds 9000 | cpe:2.3:h:cisco:mds_9000 |
| cisco | nexus 1000v | cpe:2.3:h:cisco:nexus_1000v |
| cisco | nexus 1100v | cpe:2.3:h:cisco:nexus_1100v |
| cisco | nexus 3000 | cpe:2.3:h:cisco:nexus_3000 |
| cisco | nexus 3016 | cpe:2.3:h:cisco:nexus_3016 |
| cisco | nexus 3016q | cpe:2.3:h:cisco:nexus_3016q |
| cisco | nexus 3048 | cpe:2.3:h:cisco:nexus_3048 |
and 35 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco firepower extensible operating systemup to 2.3 inclusive
- cisco fxos2.3
- cisco nx-osup to 6.0 inclusive
- cisco nx-osup to 2.2 inclusive
- cisco nx-osup to 5.2 inclusive
- cisco nx-osup to 4.1 inclusive
- cisco nx-os2.5
- cisco nx-os3.0
- cisco nx-os3.1
- cisco nx-os3.2
- cisco nx-os5.2
- cisco nx-os6.1
- cisco nx-os6.2
- cisco nx-os6.3
- cisco nx-os7.0
- cisco nx-os7.0(3)i3(1)
- cisco nx-os7.1(0.1)
- cisco nx-os7.3
- cisco nx-os8.1
- cisco nx-os8.2
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2015-6435An unspecified CGI script in Cisco FX-OS before 1.1.2 on Firepower 9000 devices and Cisco Unified Computing System (UCS) Manager before 2.2(42Plan
- CVE-2020-3172Cisco FXOS and NX-OS Software Cisco Discovery Protocol Arbitrary Code Execution and Denial of Service Vulnerability36Monitor
- CVE-2017-12277A vulnerability in the Smart Licensing Manager service of the Cisco Firepower 4100 Series Next-Generation Firewall (NGFW) and Firepower 930036Monitor
- CVE-2020-3456Cisco FXOS Software Firepower Chassis Manager Cross-Site Request Forgery Vulnerability35Monitor
- CVE-2020-3517Cisco FXOS and NX-OS Software Cisco Fabric Services Denial of Service Vulnerability34Monitor
- CVE-2020-3459Cisco FXOS Software for Firepower 4100/9300 Series Command Injection Vulnerability31Monitor
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
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-770 · Allocation of Resources Without Limits or ThrottlingCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- FloodingCAPEC-125likelihood: High · Medium
- Excessive AllocationCAPEC-130likelihood: Medium · Medium
- XML Ping of the DeathCAPEC-147likelihood: Low · Medium
- Exponential Data ExpansionCAPEC-197likelihood: High · Medium
- Serialized Data Parameter BlowupCAPEC-229likelihood: High · High
- Serialized Data with Nested PayloadsCAPEC-230likelihood: Medium · High
- Oversized Serialized Data PayloadsCAPEC-231likelihood: Medium · High
- HTTP DoSCAPEC-469Low
ATT&CK techniques
- Network Denial of Service:Direct Network FloodT1498.001
- Network Denial of Service:Reflection AmplificationT1498.002
- Endpoint Denial of ServiceT1499
- Endpoint Denial of Service: OS Exhaustion FloodT1499.001
- Endpoint Denial of Service:Service Exhaustion FloodT1499.002
- Endpoint Denial of Service:Application Exhaustion FloodT1499.003
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; 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 helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- www.securityfocus.com/bid/101493
- www.securitytracker.com/id/1039614
- support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbst03846en_us
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171018-aaavty
Vendor advisories and official records. Exploit/PoC links are deliberately left out.