# CVE-2026-25742: Zulip: Anonymous File Access After Disabling Spectator Access

> Attackers can anonymously access files and topic history from web-public streams even after disabling spectator access, exposing sensitive data.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Apr 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-f47p-xjqq-g28w

## What is CVE-2026-25742?

CVE-2026-25742 is a medium-severity missing authorization vulnerability in zulip, published on 3 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Zulip is an open-source team collaboration tool. Prior to version 11.6, Zulip is an open-source team collaboration tool. From version 1.4.0 to before version 11.6, even after spectator access (enable_spectator_access / WEB_PUBLIC_STREAMS_ENABLED) is disabled, attachments originating from web-public streams can still be retrieved anonymously. As a result, file contents remain accessible even after public access is intended to be disabled. Similarly, even after spectator access is disabled, the /users/me/<stream_id>/topics endpoint remains reachable anonymously, allowing retrieval of topic history for web-public streams. This issue has been patched in version 11.6. This issue has been patched in version 11.6.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-25742?

It affects 1 product.


Products: Zulip Zulip.

## How do I fix CVE-2026-25742?

No fix has been published for CVE-2026-25742 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-25742 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25742 exists.

## Other vulnerabilities in zulip

- [CVE-2021-43799](https://insights.sbomify.com/CVE-2021-43799/): RabbitMQ exposes ports with weak default secrets in Zulip Server (high 8.6)
- [CVE-2022-35962](https://insights.sbomify.com/CVE-2022-35962/): Crafted link in Zulip message can cause disclosure of credentials (high 8.0)
- [CVE-2016-4427](https://insights.sbomify.com/CVE-2016-4427/): Auth bypass in zulip (high 7.5)
- [CVE-2021-3866](https://insights.sbomify.com/CVE-2021-3866/): Cross-site Scripting (XSS) - Stored in zulip/zulip (medium 6.8)
- [CVE-2023-28623](https://insights.sbomify.com/CVE-2023-28623/): Unauthorized user can register an account in specific configurations in Zulip (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25742 and fix it if it is affected.

What it is: CVE-2026-25742 is a medium-severity missing authorization vulnerability in zulip, published on 3 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25742 exists.

Affected product: zulip. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-25742/ (Markdown: https://insights.sbomify.com/CVE-2026-25742/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25742
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25742
- OSV: https://osv.dev/vulnerability/CVE-2026-25742

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25742/
Summaries are generated and may contain mistakes; the official description above is the record.