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)

EPSS: 0.001 (2.8th percentile) — read the EPSS interpretation.

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.

Affected products

Weakness classification (CWE)

References

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.