Auth bypass in Modoboa
CVE-2026-113599
Modoboa before 2.8.0 contains an insecure direct object reference vulnerability that allows authenticated users to create auto-reply messages for arbitrary mailboxes by supplying another user's mbox value. Attackers can POST to /api/v2/armessages/ to inject attacker-controlled auto-reply subject and content into victims' settings or break their auto-reply management via MultipleObjectsReturned errors.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/modoboa/modoboa/issues/3945 (issue-tracking)
- github.com/modoboa/modoboa/commit/e0a4e3b9ee8ad84dba46e4c0f04cbbe7cf78c38d (patch)
- github.com/modoboa/modoboa/releases/tag/2.8.0 (release-notes)
- github.com/modoboa/modoboa/blob/2.7.2/modoboa/autoreply/api/v2/serializers.py (technical-description)
- www.vulncheck.com/advisories/modoboa-before-2.8.0-idor-via-api-v2-armessages-au… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-113599?
- CVE-2026-113599 is a medium-severity vulnerability in Modoboa, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.4/10. Published 2026-10-20.
- How severe is CVE-2026-113599?
- Medium severity. CVSS v3 base score is 5.4 out of 10.