CVE-2026-40112

MEDIUM

PraisonAI has Stored XSS via Unsanitized Agent Output in HTML Rendering (nh3 Not a Required Dependency)

Title source: cna
STIX 2.1

Description

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.

References (1)

Core 1
Core References

Scores

CVSS v3 5.4
EPSS 0.0004
EPSS Percentile 11.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-79
Status published
Products (3)
MervinPraison/PraisonAI < 4.5.128
praison/praisonai < 4.5.128
pypi/PraisonAI 0 - 4.5.128PyPI
Published Apr 09, 2026
Tracked Since Apr 10, 2026