# CVE-2026-40871

> Vulnerability · severity: **HIGH** (CVSS 7.2).

## Description

mailcow: dockerized is an open source groupware/email suite based on docker. Versions prior to 2026-03b have a second-order SQL injection vulnerability in the quarantine_category field via the Mailcow API. The /api/v1/add/mailbox endpoint stores quarantine_category without validation or sanitization. This value is later used by quarantine_notify.py, which constructs SQL queries using unsafe % string formatting instead of parameterized queries. This results in a delayed (second-order) SQL injection when the quarantine notification job executes, allowing an attacker to inject arbitrary SQL. Using a UNION SELECT, sensitive data (e.g., admin credentials) can be exfiltrated and rendered inside quarantine notification emails. Version 2026-03b fixes the vulnerability.

## Key facts

- **CVE ID:** CVE-2026-40871
- **Published:** 2026-04-21
- **CVSS severity:** HIGH
- **CVSS base score:** 7.2
- **CWE codes:** CWE-20, CWE-89, CWE-116, CWE-564

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40871

## Citation

> AI Analytics. CVE-2026-40871. Retrieved 2026-07-23 from https://api.ai-analytics.org/cve/CVE-2026-40871. Derived from NIST NVD. Licensed CC0.

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