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CVE Record

CVE-2020-5420: Gorouter is vulnerable to DoS attack via invalid HTTP responses

Cloud Foundry Routing (Gorouter) versions prior to 0.206.0 allow a malicious developer with "cf push" access to cause denial-of-service to the CF cluster by pushing an app that returns specially crafted HTTP responses that crash the Gorouters.

HighCVSS 7.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2020-5420 lets an authenticated Cloud Foundry developer with cf push access crash Gorouter components by deploying an app that returns malformed HTTP responses. The business impact is service availability: routing instability can disrupt applications across the Cloud Foundry cluster.

Executive priority

Treat as a high-priority availability risk for Cloud Foundry environments, especially multi-tenant foundations or environments with broad developer push access. Patch scheduling should prioritize internet-facing or business-critical foundations.

Technical view

Cloud Foundry Gorouter versions before 0.206.0 mishandle specially crafted invalid HTTP responses from pushed applications, causing Gorouter crashes. The CVSS 3.0 score is 7.7 high, with low attack complexity but requiring low privileges and no user interaction.

Likely exposure

Exposure is most relevant to Cloud Foundry deployments running Routing/Gorouter before 0.206.0 where developers or compromised developer accounts can push applications.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires cf push access, so insider misuse or compromised developer credentials are the primary concern.

Researcher notes

Evidence supports denial of service through invalid HTTP response handling in Gorouter before 0.206.0. Do not assume remote unauthenticated exploitation; the CVE requires low privileges via cf push access. Public exploitation status is not established in the provided sources.

Mitigation direction

  • Upgrade Cloud Foundry Routing/Gorouter to version 0.206.0 or later.
  • Review the Cloud Foundry advisory for deployment-specific update guidance.
  • Restrict cf push privileges to trusted users and required spaces.
  • Monitor Gorouter crash, restart, and availability metrics after remediation.

Validation and detection

  • Inventory Cloud Foundry Routing/Gorouter versions across all foundations.
  • Confirm no Gorouter instances remain below version 0.206.0.
  • Review recent Gorouter restarts or crashes for unexplained availability events.
  • Audit developer accounts with cf push access and remove unnecessary permissions.
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

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cwe · low confidence lookup

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cve · low confidence lookup

CVE-2020-5420 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.7 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/AV:N/AC:L/PR:L/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
7.7CVSS 3.0HighCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H3.14Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

7.7High
CVSS 3.0 vector shape for CVE-2020-5420Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/AV:N/AC:L/PR:L/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
Cloud FoundryRoutingAllListed
Cloud FoundryCF DeploymentAllListed
Weakness

CWE details

CWE-754

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