CVE-2025-27149: Zulip server provides an open-source team chat that helps teams stay productive and focused. Prior to 10.0, the data export to organization administra...

Description

Zulip server provides an open-source team chat that helps teams stay productive and focused. Prior to 10.0, the data export to organization administrators feature in Zulip leaks private data. The collection of user-agent types identifying specific integrations or HTTP libraries (E.g., ZulipGitlabWebhook, okhttp, or PycURL) that have been used to access any organization on the server was incorrectly included in all three export types, regardless of if they were used to access the exported organization or not. The "public data" and "with consent" exports metadata including the titles of some topics in private channels which the administrator otherwise did not have access to, and none of the users consented to exporting and metadata for which users were in a group DM together. This vulnerability is fixed in 10.0.

Metrics

CVSS 3.1

2.7/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N

CVSS 4.0

4.6/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.26%

17.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-497

Affected Software

Vendor	Product	Versions
Zulip	Zulip Server	>= 2.1.0, < 10.0

References

https://github.com/zulip/zulip/security/advisories/GHSA-358p-x39m-99mmThird Party Advisory

Timeline

Published: Mar 31, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-27149?

Zulip server provides an open-source team chat that helps teams stay productive and focused. Prior to 10.0, the data export to organization administrators feature in Zulip leaks private data. The collection of user-agent types identifying specific integrations or HTTP libraries (E.g., ZulipGitlabWebhook, okhttp, or PycURL) that have been used to access any organization on the server was incorrectly included in all three export types, regardless of if they were used to access the exported organization or not. The "public data" and "with consent" exports metadata including the titles of some topics in private channels which the administrator otherwise did not have access to, and none of the users consented to exporting and metadata for which users were in a group DM together. This vulnerability is fixed in 10.0.

How severe is CVE-2025-27149?

CVE-2025-27149 has a CVSS score of 4.6/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.

How do I fix CVE-2025-27149?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.