VulnerabilityDeferred

CVE-2026-40871

Versions prior to 2026-03b have a second-order SQL injection vulnerability in the quarantine_category field via the Mailcow API.

HIGH 7.2EPSS 9.87%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (9.87%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1: 7.2 HIGHCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS: 9.87% probability · 95th percentile
CISA KEV: Not listed
Weakness: CWE-20, CWE-89, CWE-116, CWE-564
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.