CVE-2026-59804Public exploitNetwork attack vector

Session hijack via unauthenticated cross-origin WebSocket

Published Jul 8, 2026 · Updated Jul 8, 2026

Missing WebSocket access controls in Web Infra Midscene.js 1.10.3 and earlier allow remote attackers to hijack active bridge sessions. The Socket.IO middleware in io-server.ts accepts browser connections without validating the Origin header or requiring an authentication token, and the kill-signal branch trusts the MIDSCENE_BRIDGE_SIGNAL_KILL query parameter unconditionally. A victim must visit attacker-controlled JavaScript while bridge mode is running; the page can seize an open client slot, read or inject automation payloads, or shut down the bridge server.

CVSS severity7.6
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing WebSocket access controls in Web Infra Midscene.js 1.10.3 and earlier allow remote attackers to hijack active bridge sessions. The Socket.IO middleware in io-server.ts accepts browser connections without validating the Origin header or requiring an authentication token, and the kill-signal branch trusts the MIDSCENE_BRIDGE_SIGNAL_KILL query parameter unconditionally. A victim must visit attacker-controlled JavaScript while bridge mode is running; the page can seize an open client slot, read or inject automation payloads, or shut down the bridge server.

The record

CVE
CVE-2026-59804
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
Web Infra
Product
Midscene.js
Classifications
CWE-1385, CWE-306, T1203
Attack vector
network
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=0 <=1.10.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Web Infra · Midscene.jsversion=0 <=1.10.3

Published CVSS scores

6.8VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
7.6VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-1385Missing Origin Validation in WebSockets
CWE-306Missing Authentication for Critical Function
T1203Exploitation for Client Execution

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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