Username disclosure via authentication timing oracle
Published Sep 21, 2026 · Updated Sep 21, 2026
Observable timing discrepancies in Tinyauth before 5.1.0 allow remote attackers to disclose valid local usernames through login attempts. Missing-user paths in loginHandler and basicAuth return without bcrypt work, while existing-user paths verify a password hash and respond more slowly. Exploitation requires a reachable login or Basic Authentication path and local-user configuration; the result supports targeted credential attacks.
Summary
What happened
Observable timing discrepancies in Tinyauth before 5.1.0 allow remote attackers to disclose valid local usernames through login attempts. Missing-user paths in loginHandler and basicAuth return without bcrypt work, while existing-user paths verify a password hash and respond more slowly. Exploitation requires a reachable login or Basic Authentication path and local-user configuration; the result supports targeted credential attacks.
The record
- CVE
- CVE-2026-77582
- Published
- Sep 21, 2026
- Updated
- Sep 21, 2026
- Vendor
- Tinyauth
- Product
- Tinyauth
- Classifications
- CWE-208, T1087
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 21, 2026CVE publishedPublication date reported by the CVE source.
- Sep 21, 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.
- Affected versionversion=< 5.1.0
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Public exploit references
- Tinyauth timing-oracle proof of conceptproof of concept · demonstrated
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
Get started to see how Hinoki identifies affected software and validates exploitability in your environment.
Get started