Missing Authorization in Private Server Member Enumeration

stoatchat before 0.15.0 contains a missing authorization vulnerability in the Subscribe message handler that allows authenticated attackers to enumerate members and monitor profile updates of private servers without membership. Attackers can subscribe to any server's member-update topic by sending a Subscribe message with an arbitrary server ID, receiving live UserUpdate events including display names, avatars, and status changes for members they should not have access to.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2026-74869 represents a critical authorization bypass in stoatchat versions before 0.15.0 that enables authenticated attackers to enumerate and monitor members of private servers without legitimate access. The vulnerability exists in the Subscribe message handler, which fails to validate whether a user should have permission to access a specific server's member-update topic. This allows attackers to arbitrarily specify server IDs and receive live UserUpdate events containing sensitive information such as display names, avatars, and online status for members they should never see. Organizations using stoatchat for private communications—including enterprise teams, restricted communities, and sensitive group coordination—face exposure of member identities and activity patterns that compromise privacy and operational security.

Casky's 283 mapped skills detect the attack patterns underlying this vulnerability by correlating MITRE ATT&CK techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access) with authorization-layer analysis. Practitioners using Casky's extended reasoning capabilities would identify suspicious Subscribe message sequences where authenticated sessions request member-update topics for servers outside their membership scope, triggering CWE-862 (Missing Authorization) detection patterns. The platform would flag anomalous UserUpdate event streams flowing to unauthorized principals, recognize the enumeration pattern of arbitrarily incrementing or discovered server IDs, and correlate these signals with privilege escalation indicators—surfacing these findings as high-confidence attacks attempting to gather member intelligence from restricted communities.

Live Threat IntelligenceComing soon

Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-74869.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

cryptography · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-74869

Casky has 283 skills that investigate the attack patterns behind CVE-2026-74869. Run one and get CVSS-scored findings in 3 minutes.

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