Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
Medium, CVSS 5.1amended

Novu: Stored XSS in In-App Inbox via notification redirect.url javascript: scheme

CVE-2026-75510GHSA-8gr3-5j6f-25gp

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (@novu/js 3.18.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

  • npm @novu/js

    Affected
    <= 3.17.0
    Fixed in
    3.18.0

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
5.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N · score source
EPSS
  • CVE-2026-75510: 0.48% estimated exploitation activity in the next 30 days; percentile 41.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary The @novu/js In-App Inbox renderer passes a notification's redirect.url to window.open() with no URL-scheme validation. The value originates from a notification's call-to-action and is delivered to the recipient verbatim. An authenticated organization member (or any holder of the environment API key) creates a v1 in-app workflow whose step CTA stores cta.data = { url: "javascript:<payload", target: "self" }. The v1 message-template cta.data field is a Mongoose Mixed type, so the arbitrary target key is accepted and persisted. The server-side inbox mapper copies cta.data.url and cta.data.target into the notification's redirect object with no scheme check. Novu's v2 control schema validates redirect URLs against redirectUrlRegex (which rejects javascript:), proving the intended invariant; the v1 path and the client renderer do not enforce it. When the recipient clicks the notification, the inbox calls window.open(url, "self", "noopener noreferrer"). In Chromium browsers a…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 4 · amended ·

    Amended from ghsa record GHSA-8gr3-5j6f-25gp

  2. Revision 3 · amended ·

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

  3. Revision 2 · amended ·

    Amended from osv record GHSA-8gr3-5j6f-25gp

  4. Revision 1 · created ·

    Published from ghsa record GHSA-8gr3-5j6f-25gp

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-75510

Advisory: Novu: Stored XSS in In-App Inbox via notification redirect.url javascript: scheme
IDs: CVE-2026-75510, GHSA-8gr3-5j6f-25gp
Record: https://patchnext.com/advisories/cve-2026-75510 (revision 4, source checked 26 Oct 2026, 13:02 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @novu/js 3.18.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @novu/js: affected <= 3.17.0; fixed in 3.18.0

## Suggested inspection (read-only)
- `npm ls @novu/js --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 @novu/js.
- 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://github.com/advisories/GHSA-8gr3-5j6f-25gp (GitHub-reviewed advisory GHSA-8gr3-5j6f-25gp lists affected ranges: npm @novu/js >=0 <=3.17.0)
- Verified: https://osv.dev/vulnerability/GHSA-8gr3-5j6f-25gp (OSV record GHSA-8gr3-5j6f-25gp lists affected ranges: npm @novu/js >=0 <3.18.0 (fixed))

Commands are suggestions: review each one before running it.

Loading voting…