CVE-2026-71236: Grocy - Stored XSS via HTMLPurifier Output Double-Decode

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 &lt;, &gt;, and &amp; back to <, >, and & immediately after purification.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Attack vector

Network

Complexity

Low

Privileges

Low

User interaction

Required

Confidentiality

High

Integrity

High

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.4% · higher than 29% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

GR

grocy · grocy

0 · source: vendor