CVE-2025-25195Network attack vector

Private channel-name disclosure via overbroad event recipients

Published Feb 13, 2025 · Updated Feb 14, 2025

Information disclosure in Zulip Server 10.0-dev allows remote authenticated users to read private channel names via server events. The notify_stream_is_recently_active_update function sends activity-change events containing a private channel name to every active organization user instead of restricting recipients to users permitted to access that channel. Organization membership is required, and the leak occurs when the weekly job marks a channel inactive after 180 traffic-free days or the first later message reactivates it.

CVSS severity4.3
Medium
EPSS probability0.37%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Information disclosure in Zulip Server 10.0-dev allows remote authenticated users to read private channel names via server events. The notify_stream_is_recently_active_update function sends activity-change events containing a private channel name to every active organization user instead of restricting recipients to users permitted to access that channel. Organization membership is required, and the leak occurs when the weekly job marks a channel inactive after 180 traffic-free days or the first later message reactivates it.

The record

CVE
CVE-2025-25195
Published
Feb 13, 2025
Updated
Feb 14, 2025
Vendor
Zulip
Product
Zulip
Classifications
CWE-200
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 13, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 50256f48314250978f521ef439cafa704e056539, < 75be449d456d29fef27e9d1828bafa30174284b4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zulip · Zulipversion=>= 50256f48314250978f521ef439cafa704e056539, < 75be449d456d29fef27e9d1828bafa30174284b4

Published CVSS scores

4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo