CVE-2026-40872: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in mailcow mailcow-dockerized
CVE-2026-40872 is a critical cross-site scripting (XSS) vulnerability in mailcow-dockerized versions prior to 2026-03b. The vulnerability arises because the admin dashboard's Autodiscover logs render the EMailAddress value without HTML escaping, allowing an attacker to submit a crafted email address containing malicious HTML or JavaScript. This payload is stored in Redis and executed when an admin views the Autodiscover logs. The issue is fixed in version 2026-03b.
AI Analysis
Technical Summary
mailcow-dockerized is an open source groupware/email suite using Docker. In versions before 2026-03b, the Autodiscover logs in the admin dashboard improperly neutralize input by rendering the EMailAddress field without HTML escaping. An unauthenticated attacker can submit an Autodiscover request with a maliciously crafted EMailAddress containing HTML or JavaScript code. This payload is stored in Redis and later executed in the context of the admin dashboard when viewed, resulting in a stored cross-site scripting vulnerability. The vulnerability is identified as CWE-79 and CWE-80 and has a CVSS 4.0 score of 9.3, indicating critical severity. The vulnerability is fixed in version 2026-03b.
Potential Impact
Successful exploitation allows an unauthenticated attacker to execute arbitrary JavaScript in the context of the admin dashboard user’s browser. This can lead to administrative session compromise, unauthorized actions, or data disclosure within the mailcow admin interface. The vulnerability affects all versions prior to 2026-03b. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade mailcow-dockerized to version 2026-03b or later, where this vulnerability is fixed. Since the vendor advisory indicates the issue is resolved in 2026-03b, applying this official fix fully mitigates the risk. No additional mitigation steps are indicated or necessary beyond applying the update.
CVE-2026-40872: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in mailcow mailcow-dockerized
Description
CVE-2026-40872 is a critical cross-site scripting (XSS) vulnerability in mailcow-dockerized versions prior to 2026-03b. The vulnerability arises because the admin dashboard's Autodiscover logs render the EMailAddress value without HTML escaping, allowing an attacker to submit a crafted email address containing malicious HTML or JavaScript. This payload is stored in Redis and executed when an admin views the Autodiscover logs. The issue is fixed in version 2026-03b.
CVSS v4.0
Score 9.3critical
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
mailcow-dockerized is an open source groupware/email suite using Docker. In versions before 2026-03b, the Autodiscover logs in the admin dashboard improperly neutralize input by rendering the EMailAddress field without HTML escaping. An unauthenticated attacker can submit an Autodiscover request with a maliciously crafted EMailAddress containing HTML or JavaScript code. This payload is stored in Redis and later executed in the context of the admin dashboard when viewed, resulting in a stored cross-site scripting vulnerability. The vulnerability is identified as CWE-79 and CWE-80 and has a CVSS 4.0 score of 9.3, indicating critical severity. The vulnerability is fixed in version 2026-03b.
Potential Impact
Successful exploitation allows an unauthenticated attacker to execute arbitrary JavaScript in the context of the admin dashboard user’s browser. This can lead to administrative session compromise, unauthorized actions, or data disclosure within the mailcow admin interface. The vulnerability affects all versions prior to 2026-03b. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade mailcow-dockerized to version 2026-03b or later, where this vulnerability is fixed. Since the vendor advisory indicates the issue is resolved in 2026-03b, applying this official fix fully mitigates the risk. No additional mitigation steps are indicated or necessary beyond applying the update.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-15T15:57:41.718Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e7d08919fe3cd2cdf3fb16
Added to database: 4/21/2026, 7:31:21 PM
Last enriched: 4/29/2026, 11:36:56 AM
Last updated: 6/5/2026, 10:21:33 PM
Views: 61
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