CVE-2026-74998
Medium
Elevated severity or exploit probability.
CVSS base
7.2
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
EPSS — probability of exploitation (30 days)
0.4%
35.5th percentile
CISA KEV
Not listed
Weakness / dates
CWE-79
Published 2026-08-17 · modified 2026-09-08
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | C | Changed |
| Confidentiality | L | Low |
| Integrity | L | Low |
| Availability | N | None |
Timeline
- 2026-08-17 — Published (NVD)
- 2026-09-08 — Last modified (NVD)
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.
Affected
References
- https://github.com/roundcube/roundcubemail/commit/62d33c8a0dc3fd0dd03984220dc9709e8e0de43b
- https://github.com/roundcube/roundcubemail/commit/a2334990c02f7cb77b1a8d6fa97fcd9e1b5cd1fb
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.18
- https://github.com/roundcube/roundcubemail/releases/tag/1.7.3
- https://roundcube.net/news/2026/08/09/security-updates-1.6.18-and-1.7.3