---
id: CVE-2026-70556
title: >-
  Hubzilla  versions prior to 11.4 contains a cross-site request forgery
  vulnerability in the OAuth2 /authorize endpoint handled by
  Zotlabs\Module\Authorize::post() that allows unauthenticated attackers to
  register arbitrary OAuth2 applica…
summary: >-
  Hubzilla  versions prior to 11.4 contains a cross-site request forgery
  vulnerability in the OAuth2 /authorize endpoint handled by
  Zotlabs\Module\Authorize::post() that allows unauthenticated attackers to
  register arbitrary OAuth2 applica…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N'
cwe:
  - CWE-352
vendor: Hubzilla
product: Hubzilla
affected:
  - Hubzilla < 11.4
published: '2026-08-06'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:06:30.133'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-70556'
references:
  - url: 'https://framagit.org/hubzilla/core'
    label: disclosure@vulncheck.com
  - url: >-
      https://framagit.org/hubzilla/core/-/blob/dev/Zotlabs/Module/Authorize.php?ref_type=heads#L49
    label: disclosure@vulncheck.com
  - url: 'https://hub.volse.no/cloud/harald/Skjermopptak_20260616_095037.webm'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/hubzilla-csrf-via-oauth2-authorize-endpoint-app-registration
    label: disclosure@vulncheck.com
  - url: 'https://hub.volse.no/cloud/harald/Skjermopptak_20260616_095037.webm'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.0019
epssPercentile: 0.07686
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-06T14:07:25.691300Z'
ingestedAt: '2026-09-24T15:45:56.716Z'
---

## Overview

Hubzilla  versions prior to 11.4 contains a cross-site request forgery vulnerability in the OAuth2 /authorize endpoint handled by Zotlabs\Module\Authorize::post() that allows unauthenticated attackers to register arbitrary OAuth2 applications under an authenticated user's account by submitting a cross-origin POST request without CSRF token or Origin/Referer validation. Attackers can craft a malicious HTML form that autosubmits attacker-chosen OAuth2 parameters including client_id, client_secret, redirect_uri, and scope to silently register a persistent OAuth2 application, enabling interception of future OAuth2 authorization codes when the victim later authenticates against the attacker-controlled client.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.