Note Mark: OIDC-registered users authenticated by submitting password "null"

Exploitation

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

CVSS

9.4 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

EPSS

• CVE-2026-41571: 0.37% estimated exploitation activity in the next 30 days; percentile 30.58 (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 IsPasswordMatch in backend/db/models.go falls back to a hard-coded bcrypt("null") placeholder whenever a user has no stored password. OIDC-registered users are created with an empty password, so anyone who submits password: "null" to the internal login endpoint receives a valid session for that user. The bypass is unauthenticated and requires no user interaction. Details backend/db/models.go:36 defines the placeholder hash used by the timing-attack mitigation inside IsPasswordMatch: IsPasswordMatch (backend/db/models.go:46-58) substitutes that placeholder when the stored password is empty: OIDC-registered users are stored with an empty password at backend/services/auth.go:102-115: The internal login endpoint (POST /api/auth/token, handled at backend/services/auth.go:20-54) calls IsPasswordMatch with the caller-supplied password. For any OIDC-only user, bcrypt.CompareHashAndPassword(nullPasswordHash, []byte("null")) returns nil, the function returns true, and the server issues…

Published by the source

25 Apr 2026, 23:40 UTC

Last modified by the source

7 May 2026, 20:20 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-pxf8-6wqm-r6hh

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# Patch Next advisory brief: CVE-2026-41571

Advisory: Note Mark: OIDC-registered users authenticated by submitting password "null"
IDs: CVE-2026-41571, GHSA-pxf8-6wqm-r6hh
Record: https://patchnext.com/advisories/cve-2026-41571 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/enchant97/note-mark/backend 0.0.0-20260417132909-dea5530cc989. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/enchant97/note-mark/backend: affected < 0.0.0-20260417132909-dea5530cc989; fixed in 0.0.0-20260417132909-dea5530cc989

## Suggested inspection (read-only)
- Go github.com/enchant97/note-mark/backend: check the installed version with your package manager.

## 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 github.com/enchant97/note-mark/backend.
- 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-pxf8-6wqm-r6hh (GitHub-reviewed advisory GHSA-pxf8-6wqm-r6hh lists affected ranges: Go github.com/enchant97/note-mark/backend >=0 <0.0.0-20260417132909-dea5530cc989)

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