Nitro has an Open Redirect via Protocol-Relative URL Bypass in Wildcard Route Rules

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N · score source

EPSS

• CVE-2026-44372: 0.28% estimated exploitation activity in the next 30 days; percentile 20.50 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

A redirect route rule like: is intended to rewrite paths within the same host. Before the patch, an attacker could turn the rewrite into a cross-host redirect by sliding an extra slash in after the rule prefix. Example exploit: Nitro stripped /legacy from the matched pathname and joined the remainder against the rule's target. The remainder was //evil.com, which the join preserved verbatim, so Nitro responded with Location: //evil.com. Browsers resolve //evil.com as a protocol-relative URL against the current scheme, sending the user to https://evil.com. Are you affected? Users may be affected if all of the following are true: 1. Their project uses Nitro's routeRules with a redirect entry. 2. The target uses a / wildcard suffix to forward sub-paths (e.g. redirect: "/", redirect: "/new/", proxy: { to: "http://upstream/" }). 3. The redirect rule is not handled natively at the CDN layer. The vercel, netlify, cloudflare-pages, and edgeone presets translate routeRules.redirect into…

Published by the source

6 May 2026, 23:02 UTC

Last modified by the source

9 Jun 2026, 02:15 UTC

Source last checked

26 Oct 2026, 12:53 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-9phm-9p8f-hw5m

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-9phm-9p8f-hw5m

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# Patch Next advisory brief: CVE-2026-44372

Advisory: Nitro has an Open Redirect via Protocol-Relative URL Bypass in Wildcard Route Rules
IDs: CVE-2026-44372, GHSA-9phm-9p8f-hw5m
Record: https://patchnext.com/advisories/cve-2026-44372 (revision 3, source checked 26 Oct 2026, 12:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: nitro 3.0.260429-beta; nitropack 2.13.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm nitro: affected < 3.0.260429-beta; fixed in 3.0.260429-beta
- npm nitropack: affected < 2.13.4; fixed in 2.13.4

## Suggested inspection (read-only)
- `npm ls nitro --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls nitropack --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on nitro, nitropack.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-9phm-9p8f-hw5m (OSV record GHSA-9phm-9p8f-hw5m lists affected ranges: npm nitro >=0 =0 <2.13.4 (fixed))
- Verified: https://github.com/advisories/GHSA-9phm-9p8f-hw5m (GitHub-reviewed advisory GHSA-9phm-9p8f-hw5m lists affected ranges: npm nitro >=0 =0 <2.13.4)

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