CVE-2026-71236

Received Received - Intake

Stored XSS in Grocy API Request-Body Parser

Publication date: 2026-08-05

Last updated on: 2026-08-10

Assigner: TuranSec

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 <, >, and & back to <, >, and & immediately after purification.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-05

Last Modified

2026-08-10

Generated

2026-08-18

AI Q&A

2026-08-05

EPSS Evaluated

2026-08-17

NVD

CVE-2026-71236

EUVD

EUVD-2026-53309

Affected Vendors & Products

Vendor	Product	Version / Range
bernd_bestel	grocy	*

Helpful Resources

Exploitability

CWE

KEV

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.

Attack-Flow Graph

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.

Detection Guidance

To detect this vulnerability, inspect API responses for unescaped HTML/script tags in fields like products, recipes, stock, users, or chores. Check if HTML entities like &lt; or &gt; are being decoded back to < or > in API outputs. Review server logs for suspicious API requests modifying these fields.

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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