XSS in Mervinpraison Praisonai
CVE-2026-40112
PraisonAI is a multi-agent teams system. Prior to 4.5.128, the Flask API endpoint in src/praisonai/api.py renders agent output as HTML without effective sanitization. The _sanitize_html function relies on the nh3 library, which is not listed as a required or optional dependency in pyproject.toml. When nh3 is absent (the default installation), the sanitizer is a no-op that returns HTML unchanged. An attacker who can influence agent input (via RAG data poisoning, web scraping results, or prompt injection) can inject arbitrary JavaScript that executes in the browser of anyone viewing the API output. This vulnerability is fixed in 4.5.128.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.002 (12.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
Affected products
- Mervinpraison Praisonai — versions < 4.5.128
- Praison Praisonai
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-40112?
- CVE-2026-40112 is a medium-severity vulnerability in Mervinpraison Praisonai, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-09.
- How severe is CVE-2026-40112?
- Medium severity. CVSS v3 base score is 5.4 out of 10.