CVE-2026-77561

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.9%, top 43% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 5.3Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
55(Attend)
EG Risk 55/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
57%
KEV
Not listed

Published

September 21, 2026

Last Modified

September 24, 2026

Advisory Details (6)

Auto-updated Sep 21, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github, github_pr.
github_release Patch Available

v5.1.0

Patch available: tinyauthapp/tinyauth v5.1.0

https://github.com/tinyauthapp/tinyauth/releases/tag/v5.1.0
github_commit Patch Available

commit dade1e2c8f27 (tinyauthapp/tinyauth)

Patch available: tinyauthapp/tinyauth v5.1.0-rc.3 (contains commit dade1e2c8f27)

https://github.com/tinyauthapp/tinyauth/commit/dade1e2c8f27a23df56ac216dcaf4b37081698e7
github_commit Patch Available

commit 654b5cc436fc (tinyauthapp/tinyauth)

Patch available: tinyauthapp/tinyauth v5.1.0-alpha.2 (contains commit 654b5cc436fc)

https://github.com/tinyauthapp/tinyauth/commit/654b5cc436fc67865c1f55edf9ba9fbded50b74f
github_pr Patch Available

fix: use better limits in lockdown to limit dos attack window

Patch available: tinyauthapp/tinyauth v5.1.0-alpha.2 (PR #943 merged 2026-06-17)

https://github.com/tinyauthapp/tinyauth/pull/943
github_pr Patch Available

refactor: rework rate limit logic

Patch available: tinyauthapp/tinyauth v5.1.0-rc.3 (PR #1008 merged 2026-07-15)

https://github.com/tinyauthapp/tinyauth/pull/1008
github Patch Available🟡 PoC Available

Unauthenticated login attempts can trigger global login lockdown denial of service in Tinyauth · Advisory · tinyauthapp/tinyauth · GitHub

https://github.com/tinyauthapp/tinyauth/security/advisories/GHSA-9xhm-w3wj-xhqh

Vendor Advisories for CVE-2026-77561(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/steveiliop56/tinyauth—1.0.1-0.20260715123057-dade1e2c8f27—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 10× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-24 23:38 UTCEG score recompute
  2. 2026-09-24 22:27 UTCEG score recompute
  3. 2026-09-24 15:32 UTCEG score recompute
  4. 2026-09-24 14:04 UTCEPSS rescore
  5. 2026-09-23 17:54 UTCEPSS rescore
  6. 2026-09-22 16:50 UTCEG score recompute
  7. 2026-09-22 16:01 UTCEPSS rescore
  8. 2026-09-21 17:25 UTCEG score recompute
  9. 2026-09-21 16:55 UTCEG score recompute
  10. 2026-09-21 16:55 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Same product

3 shown

Go:github.com/steveiliop56/tinyauth

Frequently asked(5)

What is CVE-2026-77561?
CVE-2026-77561 is a medium vulnerability published on September 21, 2026. 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/usercontroller.go…
When was CVE-2026-77561 disclosed?
CVE-2026-77561 was first published in the National Vulnerability Database on September 21, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77561 actively exploited?
CVE-2026-77561 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 43.4% of all scored CVEs.
What is the CVSS score of CVE-2026-77561?
CVE-2026-77561 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-77561?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77561, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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