vulnerability / NVI-00013223 / Revision 3
Tinyauth: Unauthenticated login attempts can trigger global login lockdown denial of service
GitHub lists this reviewed advisory for github.com/steveiliop56/tinyauth. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.3 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
0.600%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.48821. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/steveiliop56/tinyauth
source listed< 1.0.1-0.20260715123057-dade1e2c8f27
### Summary Tinyauth's login rate-limit bookkeeping can enter a global lockdown mode when its in-memory login-attempt map reaches 256 distinct identifiers. Because unauthenticated `POST /api/user/login` requests for unknown usernames are recorded in this same map, a remote unauthenticated attacker can submit 257 unique bogus usernames and cause valid credentials for unrelated users to be treated as locked until `auth.loginTimeout` expires. This was confirmed against the stable `v5.0.7` release. With default configuration, `auth.loginTimeout` is 300 seconds and `auth.loginMaxRetries` is 3, so the denial lasts about 5 minutes and can be repeated. ### Details In stable `v5.0.7`, the login endpoint is registered at `internal/controller/user_controller.go:45` and accepts unauthenticated JSON credentials in `loginHandler` at `internal/controller/user_controller.go:50`. Before validating credentials, it calls `controller.auth.IsAccountLocked(req.Username)` at `internal/controller/user_controller.go:65`. When a username does not exist, the login handler records a failed login attempt for the attacker-controlled username with `controller.auth.RecordLoginAttempt(req.Username, false)` at
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-9xhm-w3wj-xhqh ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-77561 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.