What is CVE-2026-39890?

CVE-2026-39890 is a critical-severity vulnerability in Mervinpraison Praisonai, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-04-08.

How severe is CVE-2026-39890?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Mervinpraison Praisonai

CVE-2026-39890

PraisonAI is a multi-agent teams system. Prior to 4.5.115, the AgentService.loadAgentFromFile method uses the js-yaml library to parse YAML files without disabling dangerous tags (such as !!js/function and !!js/undefined). This allows an a…

Vulnerability class: Insecure Deserialization

EPSS: 0.006 (43.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Mervinpraison Praisonai — versions < 4.5.115
Praison Praisonai

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-39890?: CVE-2026-39890 is a critical-severity vulnerability in Mervinpraison Praisonai, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-04-08.
How severe is CVE-2026-39890?: Critical severity. CVSS v3 base score is 9.8 out of 10.