CVE•Published 2026-04-18•Modified 2026-04-23•1 article on news•6 live references•NVD data

CVE-2026-40487Gitroom · Postiz

Vulnerability data via NVD (ingested)

CVSS v3.1

8.9

HIGH

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

EPSS percentile

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Weaknesses (CWE)

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CWE-345Insufficient Verification of Data Authenticity CWE-434Unrestricted Upload of File with Dangerous Type

Description

Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to the server by spoofing the `Content-Type` header. The uploaded files are then served by nginx with a Content-Type derived from their original extension (`text/html`, `image/svg+xml`), enabling Stored Cross-Site Scripting (XSS) in the context of the application's origin. This can lead to session riding, account takeover, and full compromise of other users' accounts. Version 2.21.6 contains a fix.

Timeline

Published 2026-04-18

Modified 2026-04-23

External references

NVD MITRE Exploit-DB GitHub PoC Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-40487

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Gitroom Postiz"

All exposed Gitroom Postiz instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Postiz"

HTTP body or banner mentions "Postiz" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-40487