Overview
A cross-site scripting (XSS) vulnerability in Alinto SOGo v5.12.7 allows attackers to achieve remote code execution by embedding malicious SVG (Scalable Vector Graphics) objects in ICS (iCalendar) invitations. The vulnerability has been actively exploited in the wild, as confirmed by VirusTotal sightings.
Description
Alinto SOGo is an open-source webmail and groupware platform for email, calendars, contacts, and shared scheduling. It is primarily used by organizations seeking a self-hosted interface solution for existing mail infrastructure.
CVE-2026-8496
The vulnerability exists in SOGo’s handling of ICS files, where the DESCRIPTION field is rendered without proper sanitization or Content Security Policy (CSP) enforcement. When a calendar invite contains an SVG payload, such as <animate onrepeat='...'>, with JavaScript event handlers, the browser executes the script in the context of the SOGo webmail interface. This occurs during normal calendar view rendering (e.g., when a user opens or previews the calendar tab), even without explicit interaction.
Impact
Once an attacker delivers a malicious ICS file via email, any user who views the calendar will execute the embedded XSS payload, granting the attacker full read access to the victim's mailbox. This enables:
Credential theft through forced logout/login phishing
Password manager autofill hijacking
Full exfiltration of email messages, folder contents, and metadata
Extraction of contact lists and calendar data
Solution
Users are recommended to upgrade to SOGo v5.12.8 or newer. v5.12.8 addresses this issue via sanitizing ICS DESCRIPTION content and stricter handling of embedded SVG and HTML.
Acknowledgements
Thank you to Greg Lesnewich for reporting this issue. This AI-assisted vulnerability note was prepared by Alexander Curtis.
Vendor Information
One or more vendors are listed for this advisory. Please reference the full report for more information.
References
https://github.com/Alinto/sogo/commit/67ce01ec2a1a7854d8e9f615dd65afb949043e86
https://github.com/Alinto/sogo/releases/tag/SOGo-5.12.8
https://www.sogo.nu/news/2026/sogo-v5128-released.html
Other Information
CVE IDs:
CVE-2026-8496
Date Public:
2026-08-06
Date First Published: 2026-08-06
Date Last Updated: 2026-08-18 19:57 UTC
Document Revision: 5
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