Vulnerability-Lookup

CVE-2026-19377 (GCVE-0-2026-19377)

Vulnerability from cvelistv5 – Published: 2026-10-15 07:02 – Updated: 2026-10-15 14:22

Title

Improper certificate validation in Cato Client tunnel handshake

Summary

Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.

Severity

6 (Medium)


                        
                          CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-15 14:22 UTC

CWE

CWE-295 - Improper Certificate Validation

Assigner

Cato CNA under the mitre root

CNA scorecard – unranked: 4 records in the last 180 days, 10 needed details

References

1 reference

URL	Tags
https://knowledge.catonetworks.com/docs/security-…	vendor-advisory

Impacted products

5 products

Vendor	Product	Version	CPE status
Cato Networks	Cato Client for Windows	Affected: 0 , < 6.12.6 (custom)	guessed
Cato Networks	Cato Client for macOS	Affected: 0 , < 6.1.1 (custom)	guessed
Cato Networks	Cato Client for Linux	Affected: 0 , < 5.8.1 (custom)	guessed
Cato Networks	Cato Client for iOS	Affected: 0 , < 5.9 (custom)	guessed
Cato Networks	Cato Client for Android	Affected: 0 , < 5.6.2 (custom)	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-19377

Vulnerability from fkie_nvd - Published: 2026-10-15 07:17 - Updated: 2026-10-16 20:04

Severity

6.0 (Medium) - CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

Summary

Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.

References

	URL	Tags
	2505284f-8ffb-486c-bf60-e19c1097a90b	https://knowledge.catonetworks.com/docs/security-vulnerability-cve-2026-19377-that-impacts-cato-client-versions

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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          "attackVector": "ADJACENT",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.0,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "2505284f-8ffb-486c-bf60-e19c1097a90b",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-19377",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-15T14:22:50.675325Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-15T07:17:59.143",
  "references": [
    {
      "source": "2505284f-8ffb-486c-bf60-e19c1097a90b",
      "url": "https://knowledge.catonetworks.com/docs/security-vulnerability-cve-2026-19377-that-impacts-cato-client-versions"
    }
  ],
  "sourceIdentifier": "2505284f-8ffb-486c-bf60-e19c1097a90b",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        }
      ],
      "source": "2505284f-8ffb-486c-bf60-e19c1097a90b",
      "type": "Secondary"
    }
  ]
}

GHSA-V76Q-8HM2-WRX6

Vulnerability from github – Published: 2026-10-15 09:30 – Updated: 2026-10-15 09:30

Details

Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.

Severity

6.0 (Medium)


                  
                    CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

Show details on source website

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To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-19377"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-15T07:17:59Z",
    "severity": "MODERATE"
  },
  "details": "Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.",
  "id": "GHSA-v76q-8hm2-wrx6",
  "modified": "2026-10-15T09:30:33Z",
  "published": "2026-10-15T09:30:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-19377"
    },
    {
      "type": "WEB",
      "url": "https://knowledge.catonetworks.com/docs/security-vulnerability-cve-2026-19377-that-impacts-cato-client-versions"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-19377 (GCVE-0-2026-19377)

FKIE_CVE-2026-19377

GHSA-V76Q-8HM2-WRX6

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