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CVE Record

CVE-2020-3358: Cisco RV340, RV340W, RV345, and RV345P Dual WAN Gigabit VPN Routers SSL Denial of Service Vulnerability

A vulnerability in the Secure Sockets Layer (SSL) VPN feature for Cisco Small Business RV VPN Routers could allow an unauthenticated, remote attacker to cause the device to unexpectedly restart, causing a denial of service (DoS) condition. The vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request over an SSL connection to the targeted device. A successful exploit could allow the attacker to cause a reload, resulting in a DoS condition.

HighCVSS 8.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2020-3358 can let an unauthenticated remote attacker crash certain Cisco Small Business RV VPN routers by sending a malformed HTTPS request to the SSL VPN feature. The result is a device reload and service outage, not data theft or code execution based on the provided sources.

Executive priority

Treat this as a high-priority availability risk for small-office or branch connectivity. It is not presented as a breach-enabling flaw, but a remote unauthenticated outage against VPN routers can disrupt business access and incident response operations.

Technical view

The flaw is improper input validation in HTTP requests handled over SSL by the SSL VPN feature on Cisco RV340, RV340W, RV345, and RV345P routers. CVSS 3.1 is 8.6: network exploitable, low complexity, no privileges, no user interaction, changed scope, and high availability impact only.

Likely exposure

Exposure is most likely where Cisco RV340, RV340W, RV345, or RV345P routers run affected firmware and have SSL VPN reachable from untrusted networks. The bundle does not identify specific affected firmware versions, so asset and firmware validation must be mapped to Cisco guidance.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. Exploitation requires only network access to the SSL VPN service and a crafted request, but the supported impact is denial of service through router reload.

Researcher notes

Evidence supports CWE-20 improper input validation in SSL VPN HTTP request handling. The affected version data in the bundle is incomplete, listed only as Cisco Small Business RV Series Router Firmware with no versions. Avoid claiming exploitation, patches, or workarounds beyond Cisco advisory verification.

Mitigation direction

  • Review the Cisco advisory for affected firmware, fixed releases, and workarounds.
  • Prioritize firmware remediation for exposed RV340, RV340W, RV345, and RV345P routers.
  • Restrict SSL VPN access to trusted networks where business operations allow.
  • Monitor affected routers for unexpected reloads and VPN service disruption.
  • Plan replacement if devices cannot be updated according to Cisco guidance.

Validation and detection

  • Inventory Cisco RV340, RV340W, RV345, and RV345P routers.
  • Confirm firmware versions against the Cisco advisory.
  • Determine whether SSL VPN is enabled on each device.
  • Check whether SSL VPN is reachable from untrusted networks.
  • Review device uptime and logs for unexplained reloads.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-20: Exact CWE lookup

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cve · low confidence lookup

CVE-2020-3358 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.6CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.6High
CVSS 3.1 vector shape for CVE-2020-3358Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Small Business RV Series Router Firmwaren/aListed
Weakness

CWE details

CWE-20

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.