CVE-2026-77561
MEDIUMDescription
Tinyauth is an authentication and authorization server. Prior to 5.1.0, an unauthenticated remote attacker can send POST /api/user/login requests with 257 distinct nonexistent usernames to fill MaxLoginAttemptRecords and activate a global login lockdown. internal/controller/user_controller.go loginHandler passes each attacker-controlled identifier to internal/service/auth_service.go RecordLoginAttempt, which invokes lockdownMode after the map reaches its cap. IsAccountLocked checks that global state before validating unrelated accounts, causing valid users to receive HTTP 429 until auth.loginTimeout expires, approximately 300 seconds by default. The attack can be repeated, but existing authenticated sessions are not invalidated. This issue is fixed in version 5.1.0.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
TridentStack Control tracks known vulnerabilities across your Windows, macOS, and Linux fleet and shows the fix as soon as one is published. See how it works
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploit Intelligence
Moderate risk: more likely to be exploited than 49% of all known CVEs.
References
Related Vulnerabilities
Other CWE-307 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2019-17240 | Critical | 9.8 | 40% | - | - |
| CVE-2023-29301 | High | 7.5 | 35% | - | - |
| CVE-2023-22960 | High | 7.5 | 28% | - | Fix |
| CVE-2020-15906 | Critical | 9.8 | 27% | - | Fix |
| CVE-2016-9361 | Critical | 9.8 | 20% | - | - |
| CVE-2024-39225 | Critical | 9.8 | 14% | - | - |
Common questions
How do I fix CVE-2026-77561?
No published fix for CVE-2026-77561 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-77561 being actively exploited?
Not that we know of. CVE-2026-77561 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.60% is the estimated probability that it will be exploited in the next 30 days. That is higher than 49% of all scored CVEs.
How severe is CVE-2026-77561?
CVE-2026-77561 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-77561
Markdown
[](https://tridentstack.com/cve/CVE-2026-77561)HTML
<a href="https://tridentstack.com/cve/CVE-2026-77561"><img src="https://tridentstack.com/cve/badge/CVE-2026-77561.svg" alt="CVE-2026-77561"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-24.