Vulnerability Description
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Roundcube | Webmail | >= 1.6.0, < 1.6.18 |
Related Weaknesses (CWE)
References
- https://github.com/roundcube/roundcubemail/commit/62d33c8a0dc3fd0dd03984220dc970Patch
- https://github.com/roundcube/roundcubemail/commit/a2334990c02f7cb77b1a8d6fa97fcdPatch
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.18Release Notes
- https://github.com/roundcube/roundcubemail/releases/tag/1.7.3Release Notes
- https://roundcube.net/news/2026/08/09/security-updates-1.6.18-and-1.7.3Vendor Advisory
FAQ
What is CVE-2026-74998?
CVE-2026-74998 is a vulnerability with a CVSS score of 7.2 (HIGH). In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scrip...
How severe is CVE-2026-74998?
CVE-2026-74998 has been rated HIGH with a CVSS base score of 7.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-74998?
Check the references section above for vendor advisories and patch information. Affected products include: Roundcube Webmail.