CVE-2026-71236
Received Received - Intake

Stored XSS in Grocy API Request-Body Parser

Publication date: 2026-08-05

Last updated on: 2026-08-05

Assigner: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

Description
Grocy's API request-body parser (controllers/Api/BaseApiController.php, GetParsedAndFilteredRequestBody) purifies incoming field values with HTMLPurifier, then manually reverses HTML-entity encoding of the resulting output by replacing &amp;lt;, &amp;gt;, and &amp;amp; back to <, >, and & immediately after purification. This double-decode reconstructs live HTML/script tags from the entity-encoded form that HTMLPurifier produced to neutralize them, re-introducing stored XSS across API-writable fields (products, recipes, stock, users, chores, and others) that are rendered elsewhere without re-sanitization.

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Meta Information

Published
2026-08-05
Last Modified
2026-08-05
Generated
2026-08-05
AI Q&A
2026-08-05
EPSS Evaluated
N/A
NVD
CVE-2026-71236
EUVD
EUVD-2026-53309

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
bernd_bestel grocy *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This vulnerability involves a stored cross-site scripting (XSS) flaw in Grocy's API. The issue occurs when HTML-encoded input is purified by HTMLPurifier, then incorrectly decoded back to raw HTML tags. This re-enables malicious scripts in API-writable fields like products or users, which are later rendered without proper sanitization.

Impact Analysis

An attacker could inject malicious scripts into Grocy's API fields. When other users view these fields, the scripts execute in their browsers, potentially stealing session cookies, credentials, or sensitive data. This could lead to unauthorized account access or data breaches.

Compliance Impact

This vulnerability could violate GDPR's data protection requirements by enabling unauthorized access to personal data. For HIPAA, it may compromise protected health information if Grocy is used in healthcare contexts. Both standards mandate protecting against such breaches.

Mitigation Strategies

Update Grocy to the latest version immediately to patch the XSS vulnerability in API-writable fields. Review and restrict API access permissions to trusted users only. Monitor network traffic for suspicious activity involving HTML/script tag patterns.

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