CVE-2026-5026CWE-79

Langflow - Stored XSS via Malicious SVG Upload

High · published March 27, 2026

CVSS v4.0
7.0
EPSS
0%
Percentile
17.8
In the wild
Unconfirmed
What it is

The '/api/v1/files/images/{flow_id}/{file_name}' endpoint serves SVG files with the 'image/svg+xml' content type without sanitizing their content.

Since SVG files can contain embedded JavaScript, an attacker can upload a malicious SVG that executes arbitrary JavaScript when viewed by other users, leading to stored cross-site scripting (XSS). This allows stealing authentication tokens stored in cookies, including JWT access and refresh tokens.

The record
Technical detail
CVSS v4.0
7.0 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS
0.00267 · 17.8th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-03-27T14:50Z
EPSS history
Timeline
  • 27 MAR 14:50Z
    Langflow - Stored XSS via Malicious SVG Upload
    cvelistv5