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5.3
CVE-2026-35544EXPLOITEDPATCHED
roundcube · roundcube webmail

CVE-2026-35544: An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitiz

Description

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.

Affected Products

VendorProductVersions
roundcuberoundcube webmailcomposer/roundcube/roundcubemail: >= 1.7-beta, < 1.7-rc5, < 1.5.15, < 1.6.15, < 1.7-rc6

Also Affects

Downstream vendors/products affected by this vulnerability

VendorProductSourceConfidence
open sourceroundcubecert_advisory90%

References

  • https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14
  • https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5
  • https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0
  • https://github.com/roundcube/roundcubemail/releases/tag/1.6.14
  • https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662
  • https://github.com/roundcube/roundcubemail/releases/tag/1.5.14
  • https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7

Related News (4 articles)

Tier B
BSI Advisories4h ago
[UPDATE] [mittel] Roundcube: Mehrere Schwachstellen
→ No new info (linked only)
Tier C
VulDB4d ago
CVE-2026-35544 | Roundcube Webmail up to 1.5.13/1.6.13 HTML Mail Message resource transfer
→ No new info (linked only)
Tier B
CCCS Canada7d ago
Roundcube security advisory (AV26-300)
→ No new info (linked only)
Tier B
CERT-FR8d ago
Vulnérabilité dans Roundcube (30 mars 2026)
→ No new info (linked only)
CVSS 3.15.3 MEDIUM
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CISA KEV❌ No
Actively exploited✅ Yes
Patch available
roundcube/roundcubemail@1.7-rc5
CWECWE-669
PublishedApr 3, 2026
Last enriched4d agov2
Tags
security policy bypasswebmailroundcube
Trending Score71
Source articles4
Independent4
Info Completeness9/14
Missing: epss, kev, exploit, iocs, mitre_attack

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Related CVEs (5)

MEDIUMCVE-2026-35542EXP
CVE-2026-35542: An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. The remote image blocking feature can be bypassed
Trending: 63
MEDIUMCVE-2026-35540EXP
CVE-2026-35540: An issue was discovered in Roundcube Webmail 1.6.0 before 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization
Trending: 53
MEDIUMCVE-2026-35545
CVE-2026-35545: An issue was discovered in Roundcube Webmail before 1.5.15 and 1.6.15. The remote image blocking feature can be bypassed
Trending: 44
MEDIUMCVE-2026-35543
CVE-2026-35543: An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. The remote image blocking feature can be bypassed
Trending: 44
MEDIUMCVE-2026-35541
CVE-2026-35541: An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Incorrect password comparison in the password plu
Trending: 34

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Verification

State: unverified
Confidence: 0%

Vulnerability Timeline

CVE Published
Apr 3, 2026
Discovered by ZDM
Apr 3, 2026
Updated: affectedVersions, severity, activelyExploited
Apr 3, 2026
Actively Exploited
Apr 3, 2026
Exploit Available
Apr 3, 2026
Patch Available
Apr 3, 2026

Version History

v2
Last enriched 4d ago
v2Tier C4d ago

Updated affected versions to include 1.5.13 and 1.6.13, changed severity to HIGH, and noted that no exploit exists.

affectedVersionsseverityactivelyExploited
via VulDB
v14d ago

Initial creation