CVE-2026-45797

MEDIUM

HeyForm Vulnerable to Stored XSS via Unauthenticated SVG File Upload

Title source: cna
STIX 2.1

Description

HeyForm is an open-source form builder. Prior to version 3.0.0-rc.7, the `/api/upload` endpoint allows unauthenticated file uploads including SVG files. Uploaded SVGs are stored in the static assets directory and served with `Content-Type: image/svg+xml` by Express's serve-static middleware, allowing an attacker to achieve stored cross-site scripting (XSS) on the heyform domain without any authentication. Version 3.0.0-rc.7 contains a patch for the issue.

References (2)

Core 2

Scores

CVSS v4 6.4
EPSS 0.0040
EPSS Percentile 33.2%
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-434 CWE-79
Status published
Products (1)
heyform/heyform < 3.0.0-rc.7
Published Jul 20, 2026
Tracked Since Jul 20, 2026