Cisco FXOS and NX-OS Software Link Layer Discovery Protocol Denial of Service Vulnerability
A vulnerability in the Link Layer Discovery Protocol (LLDP) implementation for Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition when the device unexpectedly reloads. The vulnerability is due to improper input validation of certain type, length, value (TLV) fields of the LLDP frame header. An attacker could exploit this vulnerability by sending a crafted LLDP packet to an interface on the targeted device. A successful exploit could allow the attacker to cause the switch to reload unexpectedly.
- Published
- Oct 17, 2018
- Updated
- Jun 16, 2026
- EPSS
- 0.8% · 54th percentile
- CWE
- CWE-20
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.8%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 5.3
- CNA · cisco
- 8.8
- 3.5 point gap
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
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 helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | nx-os | cpe:2.3:o:cisco:nx-os |
| cisco | nexus 7000 10-slot | cpe:2.3:h:cisco:nexus_7000_10-slot |
| cisco | nexus 7000 18-slot | cpe:2.3:h:cisco:nexus_7000_18-slot |
| cisco | nexus 7000 4-slot | cpe:2.3:h:cisco:nexus_7000_4-slot |
| cisco | nexus 7000 9-slot | cpe:2.3:h:cisco:nexus_7000_9-slot |
| cisco | nexus 7700 10-slot | cpe:2.3:h:cisco:nexus_7700_10-slot |
| cisco | nexus 7700 18-slot | cpe:2.3:h:cisco:nexus_7700_18-slot |
| cisco | nexus 7700 2-slot | cpe:2.3:h:cisco:nexus_7700_2-slot |
| cisco | nexus 7700 6-slot | cpe:2.3:h:cisco:nexus_7700_6-slot |
| cisco | firepower extensible operating system | cpe:2.3:o:cisco:firepower_extensible_operating_system |
| cisco | firepower 9300 | cpe:2.3:h:cisco:firepower_9300 |
| cisco | ucs | cpe:2.3:h:cisco:ucs |
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 systemr231
- cisco nx-os12.3(1e)
- cisco nx-os3.2(3d)c
- cisco nx-os6.0(4)
- cisco nx-os6.1(3)s2
- cisco nx-osr231
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 NX-OS Software
- unspecified and later · before 6.2(1)affected
Cisco Firepower 4100 Series Next-Generation Firewalls
- unspecified and later · before <2.3.1.58affected
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-20399Cisco NX-OS Software CLI Command Injection VulnerabilityKEV57Plan
- CVE-2018-0301A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to craft a packet to the manag44Plan
- CVE-2016-1453Buffer overflow in the Overlay Transport Virtualization (OTV) GRE feature in Cisco NX-OS 5.0 through 7.3 on Nexus 7000 and 7700 devices allo41Plan
- CVE-2018-0310A vulnerability in the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, remot40Plan
- CVE-2022-20650Cisco NX-OS Software NX-API Command Injection Vulnerability39Monitor
- CVE-2016-1341Cisco NX-OS 7.0(1)N1(1), 7.0(1)N1(3), and 7.0(4)N1(1) on Nexus 2000 Fabric Extender devices has a blank root password, which allows local us39Monitor
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
- Someone on the same network segment can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Adjacent
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/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)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- www.securityfocus.com/bid/105674
- www.securitytracker.com/id/1041919
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181017-fxnx-os-dos
Vendor advisories and official records. Exploit/PoC links are deliberately left out.