Auth bypass in Spip
CVE-2026-72709
SPIP before 4.4.18 contains a missing authorization vulnerability in the administrative action endpoints under ecrire/action/ that allows unauthenticated attackers to perform privileged actions by supplying a valid HMAC-SHA256 nonce without any server-side permission check via autoriser(). Attackers can obtain a valid nonce, compute it for any action as the anonymous user, and invoke the editer_auteur action directly over HTTP to reset the password of any user account, including the administrator.
Vulnerability class: Broken Access Control
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (technical-description, exploit)
- disclosure@vulncheck.com (release-notes, patch)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-72709?
- CVE-2026-72709 is a critical-severity vulnerability in Spip, classified under Missing Authorization. CVSS score: 9.8/10. Published 2026-09-11.
- How severe is CVE-2026-72709?
- Critical severity. CVSS v3 base score is 9.8 out of 10.