CVE-2026-91201Network attack vectorHinoki check available

OAuth token disclosure via wildcard postMessage

Published Sep 14, 2026 · Updated Sep 14, 2026

Token disclosure in Arc53 DocsGPT 0 through 0.20.0 allows remote attackers to steal OAuth connector sessions through a crafted opener page. The callback-status endpoint sends the connector session token and provider email to window.opener with postMessage targetOrigin set to "*" instead of restricting the recipient origin. Exploitation requires a victim to authorize a connector from an attacker-controlled opener, after which the stolen token permits connector disconnection.

CVSS severityUnavailable
Unscored
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Token disclosure in Arc53 DocsGPT 0 through 0.20.0 allows remote attackers to steal OAuth connector sessions through a crafted opener page. The callback-status endpoint sends the connector session token and provider email to window.opener with postMessage targetOrigin set to "*" instead of restricting the recipient origin. Exploitation requires a victim to authorize a connector from an attacker-controlled opener, after which the stolen token permits connector disconnection.

The record

CVE
CVE-2026-91201
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
Arc53
Product
DocsGPT
Classifications
T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 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 <=0.20.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Arc53 · DocsGPTversion=0 <=0.20.0

Published CVSS scores

No CVSS assessment is available in this record.

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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