MEDIUM Severity

CVE-2025-47930

Zulip "Who can create public channels" access control mechanism flawed in version 10.0 - 10.2

Overview

This vulnerability affects Zulip team chat application versions 10.0 - 10.2. It allows the circumvention of "Who can create public channels" access control mechanism through a loophole that's exploited by changing the channel's privacy settings to public.

Technical Details

The flaw resides in the access control mechanism of Zulip versions 10.0 - 10.2. An unauthorized user can create a private or web-public channel, and then manipulate its privacy setting to public. A patch is provided in version 10.3.

CVSS Metrics

  • Attack vector: NETWORK
  • Attack complexity: LOW
  • Privileges Required: LOW
  • User Interaction: NONE
  • Vulnerability Confidentiality: NONE
  • Vulnerability Integrity: LOW
  • Vulnerability Availability: NONE

Impact

This vulnerability allows any user to create a public channel, even when not permitted to do so, by exploiting the flaw in the access control system.

Recommendations

Upgrade to Zulip version 10.3 that contains a patch for this vulnerability.

Threat Metrics

  • "cvss_score": 5.3
  • "severity": "MEDIUM"
  • "attack_vector": "NETWORK"
  • "attack_complexity": "LOW"
  • "privileges_required": "LOW"
  • "user_interaction": "NONE"
  • "vuln_integrity_impact": "LOW"