What’s Vulnerable › Vulnerabilities

CVE-2026-40263: Note Mark: Username Enumeration via Login Endpoint Timing Side-Channel

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-17 · updated 2026-10-26
• Weakness: CWE-208

Description

Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the login endpoint performs bcrypt password verification only when the supplied username exists, returning immediately for nonexistent usernames. This timing discrepancy allows unauthenticated attackers to enumerate valid usernames by measuring response times, enabling targeted credential attacks. This issue has been fixed in version 0.19.2.

Affected products

• enchant97 note-mark: before 0.19.2

References

• https://github.com/enchant97/note-mark/commit/cf4c6f6acf70b569d80396d323b067c00d45c034
• https://github.com/enchant97/note-mark/security/advisories/GHSA-w6m9-39cv-2fwp
• https://github.com/enchant97/note-mark/security/advisories/GHSA-w6m9-39cv-2fwp

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