CVE-2026-40871 | mailcow mailcow-dockerized prior 2026-03b API quarantine_category input validation (GHSA-r8fq-wrfm-cj2q)

VDB-358585 · CVE-2026-40871 · GHSA-R8FQ-WRFM-CJ2Q MAILCOW MAILCOW-DOCKERIZED PRIOR 2026-03B API QUARANTINE_CATEGORY INPUT VALIDATION HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 5.8 $0-$5k 2.29+ Summaryinfo A vulnerability has been found in mailcow mailcow-dockerized and classified as problematic. The impacted element is an unknown function of the component API. This manipulation of the argument quarantine_category causes input validation. This vulnerability is registered as CVE-2026-40871. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded. Detailsinfo A vulnerability was found in mailcow mailcow-dockerized. It has been declared as problematic. Affected by this vulnerability is an unknown part of the component API. The manipulation of the argument quarantine_category with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is: 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. The advisory is shared at github.com. This vulnerability is known as CVE-2026-40871 since 04/15/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation requires an enhanced level of successful authentication. Technical details are known, but no exploit is available. Upgrading to version 2026-03b eliminates this vulnerability. Productinfo Type Virtualization Software Vendor mailcow Name mailcow-dockerized Website Product: https://github.com/mailcow/mailcow-dockerized/ CPE 2.3info 🔒 CPE 2.2info 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 5.9 VulDB Meta Temp Score: 5.8 VulDB Base Score: 4.7 VulDB Temp Score: 4.5 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 7.2 CNA Vector (GitHub_M): 🔒 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Input validation CWE: CWE-20 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: mailcow-dockerized 2026-03b Timelineinfo 04/15/2026 CVE reserved 04/21/2026 +6 days Advisory disclosed 04/21/2026 +0 days VulDB entry created 04/21/2026 +0 days VulDB entry last update Sourcesinfo Product: github.com Advisory: GHSA-r8fq-wrfm-cj2q Status: Confirmed CVE: CVE-2026-40871 (🔒) GCVE (CVE): GCVE-0-2026-40871 GCVE (VulDB): GCVE-100-358585 scip Labs: https://www.scip.ch/en/?labs.20171019 Entryinfo Created: 04/21/2026 22:35 Changes: 04/21/2026 22:35 (65) Complete: 🔍 Cache ID: 99:096:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸