Flowise: Mass Assignment in PUT /api/v1/user Allows Authenticated Users to Override Password Hash and Bypass Password Change Verification

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-56276: 0.37% estimated exploitation activity in the next 30 days; percentile 30.51 (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.

Summary A Mass Assignment vulnerability in the PUT /api/v1/user endpoint allows authenticated users to directly modify restricted user fields, including the credential (password hash), bypassing the intended password change workflow. Because the endpoint forwards the entire request body to the service layer without filtering, an attacker can override the credential field without providing the current password. This bypasses several security protections including: - old password verification - password hashing enforcement - password policy validation - session invalidation on password change While the vulnerability cannot be used to modify other users due to an ID check in the controller, it allows attackers who obtain a temporary session (e.g., via token theft or XSS) to establish persistent account access. Details The endpoint PUT /api/v1/user allows authenticated users to update their user profile. The controller checks that the authenticated user matches the provided id,…

Published by the source

20 May 2026, 15:44 UTC

Last modified by the source

8 Jul 2026, 08:26 UTC

Source last checked

26 Oct 2026, 12:52 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-59fh-9f3p-7m39

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-59fh-9f3p-7m39

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# Patch Next advisory brief: CVE-2026-56276

Advisory: Flowise: Mass Assignment in PUT /api/v1/user Allows Authenticated Users to Override Password Hash and Bypass Password Change Verification
IDs: CVE-2026-56276, GHSA-59fh-9f3p-7m39
Record: https://patchnext.com/advisories/cve-2026-56276 (revision 3, source checked 26 Oct 2026, 12:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: flowise 3.1.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm flowise: affected <= 3.1.1; fixed in 3.1.2

## Suggested inspection (read-only)
- `npm ls flowise --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 flowise.
- 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-59fh-9f3p-7m39 (OSV record GHSA-59fh-9f3p-7m39 lists affected ranges: npm flowise >=0 <3.1.2 (fixed))
- Verified: https://github.com/advisories/GHSA-59fh-9f3p-7m39 (GitHub-reviewed advisory GHSA-59fh-9f3p-7m39 lists affected ranges: npm flowise >=0 <=3.1.1)

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