CSRF in Hubzilla
CVE-2026-70556
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.
Vulnerability class: CSRF (Cross-Site Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (8.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 8.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Hubzilla — versions 11.4, 0
Weakness classification (CWE)
References
- framagit.org/hubzilla/core (product)
- hub.volse.no/cloud/harald/Skjermopptak_20260616_095037.webm (technical-description)
- framagit.org/hubzilla/core/-/blob/dev/Zotlabs/Module/Authorize.php (patch)
- www.vulncheck.com/advisories/hubzilla-csrf-via-oauth2-authorize-endpoint-app-re… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-70556?
- CVE-2026-70556 is a medium-severity vulnerability in Hubzilla, classified under Cross-Site Request Forgery (CSRF). CVSS score: 4.3/10. Published 2026-08-06.
- How severe is CVE-2026-70556?
- Medium severity. CVSS v3 base score is 4.3 out of 10.