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Rv340 Firmware CVE-2021-1473

CRITICAL
Buffer Overflow (CWE-119)
2021-04-08 psirt@cisco.com
9.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could corrupt memory to execute arbitrary code or crash the application by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Emergency Immediate action required. Why: CRITICAL + EPSS > 30%, no patch available.
No patch listed yet 64.2% exploitation probability (EPSS)

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AnalysisAI

Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use memory-safe languages or bounds-checking. Enable ASLR, DEP/NX, stack canaries. Use safe string functions.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Buffer Overflow (CWE-119), which allows attackers to corrupt memory to execute arbitrary code or crash the application. Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers. A remote attacker could execute arbitrary commands or bypass authentication and upload files on an affected device. For more information about these vulnerabilities, see the Details section of this advisory. Affected products include: Cisco Rv340 Firmware, Cisco Rv340W Firmware, Cisco Rv345 Firmware, Cisco Rv345P Firmware.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionNVD

Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers. A remote attacker could execute arbitrary commands or bypass authentication and upload files on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Threat Intelligence Overview

EPSS Score
64.2%
Top 1% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC Yes
EPSS 64.2%
Patch available No
Active threat Yes
Deciding rule
CRITICAL + EPSS > 30%, no patch available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Immediate
Exploitation· derived
Active
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
High

Priority Score

148
Low Medium High Critical
KEV: 0
EPSS: +64
CVSS: +49
PoC: +20
Weaponized: +15
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Affected Products (CPE)NVD

cpe:2.3:o:cisco:rv340_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:rv340w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:rv345_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:rv345p_firmware:*:*:*:*:*:*:*:*
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