Security Digest · Vulnerability record
CVE-2026-41571: Note Mark: OIDC-registered users authenticated by submitting password "null"
Note Mark is an open-source note-taking application.
CVSS 9.4 Critical EPSS 0.5% · p40
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5%, percentile 40: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 40% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
github.com/enchant97/note-mark/backend(Go) < 0.0.0-20260417132909-dea5530cc989, fixed in 0.0.0-20260417132909-dea5530cc989. Check your lockfile, including transitive dependencies.
What it is
Note Mark is an open-source note-taking application. In version 0.19.2, 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. This issue has been patched in version 0.19.3.
From the GitHub advisory
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:
Weakness type: CWE-287.
Product: github.com/enchant97/note-mark/backend (Go) · Assigned by: GitHub_M · Published: 2026-05-04
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/enchant97/note-mark/backend | < 0.0.0-20260417132909-dea5530cc989 | 0.0.0-20260417132909-dea5530cc989 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| enchant97 | note-mark | = 0.19.2 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.4 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L |
| GitHub | 3.1 | 9.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.48% probability of exploitation activity in the next 30 days; percentile 40.
Timeline
- — GitHub-reviewed advisory GHSA-pxf8-6wqm-r6hh published (critical)
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-pxf8-6wqm-r6hh github.com
- CVE.org record CVE-2026-41571 cve.org
- NVD entry CVE-2026-41571 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com