# CVE-2025-31478: Zulip Authentication Backend Configuration Bypass

> Attackers can create unauthorized accounts in Zulip organizations configured with SSO-only authentication and disabled email auth, bypassing access controls.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/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:** 16 Apr 2025
- **Updated:** 23 Jan 2026
- **Also known as:** GHSA-qxfv-j6vg-5rqc

## What is CVE-2025-31478?

CVE-2025-31478 is a high-severity authentication bypass vulnerability in zulip, published on 16 Apr 2025. 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. Zulip supports a configuration where account creation is limited solely by being able to authenticate with a single-sign on authentication backend, meaning the organization places no restrictions on email address domains or invitations being required to join, but has disabled the EmailAuthBackend that is used for email/password authentication. A bug in the Zulip server means that it is possible to create an account in such organizations, without having an account with the configured SSO authentication backend. This issue is patched in version 10.2. A workaround includes requiring invitations to join the organization prevents the vulnerability from being accessed.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2025-31478?

It affects 1 product.


Products: Zulip Zulip Server.

## How do I fix CVE-2025-31478?

No fix has been published for CVE-2025-31478 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-31478 being exploited?

There is no known exploitation of CVE-2025-31478 in the wild and no public exploit code.

## Other vulnerabilities in zulip

- [CVE-2019-18933](https://insights.sbomify.com/CVE-2019-18933/): Information disclosure in n/a (critical 9.8)
- [CVE-2020-15070](https://insights.sbomify.com/CVE-2020-15070/): Code injection in n/a (high 8.8)
- [CVE-2017-0910](https://insights.sbomify.com/CVE-2017-0910/): Missing authorization in Zulip Server (high 8.8)
- [CVE-2023-33186](https://insights.sbomify.com/CVE-2023-33186/): Cross-site scripting vulnerability in Zulip Server development branch via topic tooltip (high 8.2)
- [CVE-2024-36612](https://insights.sbomify.com/CVE-2024-36612/): Denial of service in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-31478 and fix it if it is affected.

What it is: CVE-2025-31478 is a high-severity authentication bypass vulnerability in zulip, published on 16 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-31478 in the wild and no public exploit code.

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-2025-31478/ (Markdown: https://insights.sbomify.com/CVE-2025-31478/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-31478
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-31478
- OSV: https://osv.dev/vulnerability/CVE-2025-31478

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-31478/
Summaries are generated and may contain mistakes; the official description above is the record.