Authentication bypass via early-exit HMAC comparison
Published Feb 6, 2026 · Updated Feb 6, 2026
Timing attack in Trilium Notes before 0.101.0 allows remote attackers to bypass sync authentication and read or write all notes. The loginSync() function compares expected and supplied HMAC hashes with JavaScript's early-exit !== operator, exposing matching-prefix length through response timing. Exploitation requires more than 100,000 requests, over 1,000 source IP addresses to evade rate limiting, and consistently stable network jitter.
Summary
What happened
Timing attack in Trilium Notes before 0.101.0 allows remote attackers to bypass sync authentication and read or write all notes. The loginSync() function compares expected and supplied HMAC hashes with JavaScript's early-exit !== operator, exposing matching-prefix length through response timing. Exploitation requires more than 100,000 requests, over 1,000 source IP addresses to evade rate limiting, and consistently stable network jitter.
The record
- CVE
- CVE-2025-68621
- Published
- Feb 6, 2026
- Updated
- Feb 6, 2026
- Vendor
- Trilium Next
- Product
- Trilium Notes
- Classifications
- CWE-208, T1110
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 6, 2026CVE publishedPublication date reported by the CVE source.
- Feb 6, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.101.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Public exploit references
- Trilium sync timing-attack proof of conceptproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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