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Vulnerability record · public intelligence
CVE-2026-66420
HIGH

MeshCentral Cross-Site WebSocket Hijacking via Origin Validation Bypass on Self-Signed Certificate Deployments

Published Jul 30, 2026 · Updated Nov 3, 2026

Severity · CVSSHIGH · Not scored
Known exploitationNot listed
EPSS / likelihood0.22%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

MeshCentral Cross-Site WebSocket Hijacking via Origin Validation Bypass on Self-Signed Certificate Deployments

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

MeshCentral 1.1.21 contains a cross-site WebSocket hijacking protection bypass vulnerability that allows unauthenticated remote attackers to hijack authenticated administrator sessions by exploiting an unconditional early return in the CheckWebServerOriginName() function within webserver.js when self-signed certificates are in use. Attackers can open cross-origin WebSocket connections to any of the twelve WebSocket endpoints, send crafted action commands to exfiltrate the server sessionKey used to sign session cookies, forge session tokens as arbitrary users, and gain full remote control of all managed devices governed by the MeshCentral instance.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
MEDIUM
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. GitHub advisory ↗
  2. Patch commit ↗
  3. Source repository ↗
  4. www.vulncheck.com ↗

Record history

Published Jul 30, 2026 · Last refreshed Nov 3, 2026