CVE-2026-59723Public exploit

Command execution via cross-origin WebSocket hijacking

Published Jul 8, 2026 · Updated Jul 8, 2026

Origin validation error in Cline before 3.0.30 allows remote attackers to execute commands through the local dashboard WebSocket. The /browser upgrade calls isAuthorizedBrowserRequest(), which returns true without ROOM_SECRET and never checks the Origin header. A developer must run cline dashboard with the default localhost configuration and visit an attacker-controlled page; injected desktopCommand frames can alter MCP settings and execute commands when the entry or an auto-approved agent session activates.

CVSS severity8.8
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in Cline before 3.0.30 allows remote attackers to execute commands through the local dashboard WebSocket. The /browser upgrade calls isAuthorizedBrowserRequest(), which returns true without ROOM_SECRET and never checks the Origin header. A developer must run cline dashboard with the default localhost configuration and visit an attacker-controlled page; injected desktopCommand frames can alter MCP settings and execute commands when the entry or an auto-approved agent session activates.

The record

CVE
CVE-2026-59723
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
Cline
Product
Cline
Classifications
CWE-346, T1189
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.0.30

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Cline · Clineversion=< 3.0.30

Published CVSS scores

8.8GitHub, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-346Origin Validation Error
T1189Drive-by Compromise

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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