Grocy: Stored XSS via HTMLPurifier Output Double-Decode

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-71236
StatePUBLISHED
AssignerTuranSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-05 11:16:26 UTC
Updated2026-08-05 13:24:48 UTC
DescriptionGrocy'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.

Risk And Classification

Primary CVSS: v3.1 8.7 HIGH from 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

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

EPSS: 0.001990000 probability, percentile 0.098920000 (date 2026-08-07)

Problem Types: CWE-79 | CWE-79 CWE-79 Cross-site Scripting

VersionSourceTypeScoreSeverityVector
3.1309f9ea4-e3e9-4c6c-b79d-e8eb01244f2cSecondary8.7HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
3.1CNADECLARED8.7HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Grocy Grocy affected Not specified

References

ReferenceSourceLinkTags
github.com/grocy/grocy 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Bobur Abdugafforov (en)

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