Zulip Server 1.5.1 and below suffer from an error in the implementation of the invite_by_admins_only setting in the Zulip group chat application server that allowed an authenticated user to invite other users to join a Zulip organization even if the organization was configured to prevent this.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts integrity (unauthorized modifications), for affected systems. Impacting 1 product from zulip organizations running these solutions should prioritize assessment and patching.
First disclosed in 2017, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.
2017-06-02T17:29:00.167
2026-05-13T00:24:29.033
Modified
CVSSv3.0: 6.5 (MEDIUM)
AV:N/AC:L/Au:S/C:N/I:P/A:N
8.0
2.9
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | zulip | zulip_server | 1.3.0 | Yes |
| Application | zulip | zulip_server | 1.3.1 | Yes |
| Application | zulip | zulip_server | 1.3.2 | Yes |
| Application | zulip | zulip_server | 1.3.3 | Yes |
| Application | zulip | zulip_server | 1.3.4 | Yes |
| Application | zulip | zulip_server | 1.3.6 | Yes |
| Application | zulip | zulip_server | 1.3.7 | Yes |
| Application | zulip | zulip_server | 1.3.8 | Yes |
| Application | zulip | zulip_server | 1.3.9 | Yes |
| Application | zulip | zulip_server | 1.3.10 | Yes |
| Application | zulip | zulip_server | 1.3.11 | Yes |
| Application | zulip | zulip_server | 1.3.12 | Yes |
| Application | zulip | zulip_server | 1.3.13 | Yes |
| Application | zulip | zulip_server | 1.4.0 | Yes |
| Application | zulip | zulip_server | 1.4.1 | Yes |
| Application | zulip | zulip_server | 1.4.2 | Yes |
| Application | zulip | zulip_server | 1.4.3 | Yes |
| Application | zulip | zulip_server | 1.5.0 | Yes |
| Application | zulip | zulip_server | 1.5.1 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For zulip's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.