# CVE-2026-49456: Waku: Open Redirect via `unstable_redirect` Helper

> Attackers can redirect users to malicious sites via the unstable_redirect helper, enabling phishing and credential theft in Waku applications.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 3 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-43fc-v873-qw85

## What is CVE-2026-49456?

CVE-2026-49456 is a low-severity vulnerability in wakujs waku, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Waku is the minimal React framework. Prior to version 1.0.0-beta.1, the unstable_redirect() helper exported from waku/router/server (packages/waku/src/router/define-router.tsx:156–161) accepts an arbitrary string and reflects it unchanged into the HTTP Location response header with no URL validation, scheme restriction, or path-only enforcement. Any application that passes user-controlled input to this helper — the natural pattern documented in the JSDoc and official fixtures — is vulnerable to open redirect attacks. An attacker who convinces a victim to click a crafted link can silently redirect the browser to an arbitrary external domain, enabling phishing, credential harvesting, and OAuth token theft. Additionally, scheme-relative URLs (//evil.example/) bypass naive https?://-only allow-list filters that developers might add as ad-hoc mitigations. This issue has been patched in version 1.0.0-beta.1.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2026-49456?

2 open source packages ship an affected version, including waku.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `waku` | npm | All versions | 1.0.0-beta.1 |
| `waku` | npm | All versions | 1.0.0-beta.1 |

## How do I fix CVE-2026-49456?

Upgrade waku to 1.0.0-beta.1 or later.

## Is CVE-2026-49456 being exploited?

There is no known exploitation of CVE-2026-49456 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49456 and fix it if it is affected.

What it is: CVE-2026-49456 is a low-severity vulnerability in wakujs waku, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-49456 in the wild and no public exploit code.

Affected packages and fixed versions:
- waku (npm): affected all versions; fixed in 1.0.0-beta.1
- waku (npm): affected all versions; fixed in 1.0.0-beta.1

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-2026-49456/ (Markdown: https://insights.sbomify.com/CVE-2026-49456/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49456
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49456
- OSV: https://osv.dev/vulnerability/CVE-2026-49456

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49456/
Summaries are generated and may contain mistakes; the official description above is the record.