Auth bypass in Talishar

CVE-2026-28428

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.

Vulnerability class: Broken Authentication

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (34.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 34.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-28428: held from 0.003 to 0.004.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

  • Talishar — versions < a9c218efa37756c9e7eed056fbff6ee03f79aefc

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-28428?
CVE-2026-28428 is a medium-severity vulnerability in Talishar, classified under Improper Authentication. CVSS score: 5.3/10. Published 2026-03-06.
How severe is CVE-2026-28428?
Medium severity. CVSS v3 base score is 5.3 out of 10.