CVE-2026-74998

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.

View graph Watch Export

CVSS v3.1

7.2 HIGH

EPSS

0.32%

probability of exploitation in 30 days

CISA KEV

Not listed

no confirmed exploitation reported

News coverage

sources referencing this CVE

EPSS Trend

Aug 19, 2026 → Sep 13, 2026

▲ 0.05pp

0.27% → 0.32% over 3 tracked changes

CVSS v3.1 Detail

Attack VectorNETWORK

Attack ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

ScopeCHANGED

ConfidentialityLOW

IntegrityLOW

AvailabilityNONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Connections

2 relationships

CWE-79

source

Timeline

disclosure → media coverage

Aug 17, 2026

Disclosure — published as a CVE record.