CVE-2026-41571Public exploitNetwork attack vector

Unauthenticated account takeover via null password fallback

Published May 4, 2026 · Updated May 4, 2026

Improper authentication in Note Mark 0.19.2 allows remote attackers to take over OIDC-created accounts through the internal login endpoint. IsPasswordMatch in backend/db/models.go substitutes a hard-coded bcrypt hash of "null" when an account has no stored password, causing the supplied password "null" to verify successfully. OIDC user creation leaves the password empty, while internal login is enabled by default, so the resulting session can read, change, or delete the victim's notes and set a persistent password.

CVSS severity9.4
Critical
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper authentication in Note Mark 0.19.2 allows remote attackers to take over OIDC-created accounts through the internal login endpoint. IsPasswordMatch in backend/db/models.go substitutes a hard-coded bcrypt hash of "null" when an account has no stored password, causing the supplied password "null" to verify successfully. OIDC user creation leaves the password empty, while internal login is enabled by default, so the resulting session can read, change, or delete the victim's notes and set a persistent password.

The record

CVE
CVE-2026-41571
Published
May 4, 2026
Updated
May 4, 2026
Vendor
Leo Spratt
Product
Note Mark
Classifications
CWE-287, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 4, 2026CVE publishedPublication date reported by the CVE source.
  2. May 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion== 0.19.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Leo Spratt · Note Markversion== 0.19.2

Published CVSS scores

9.4GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1078Valid Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo