Vulnerability Report

CVE-2026-35540

Title: Roundcube Webmail CSS sanitization leads to SSRF or Information Disclosure

SSRF

Proof Of Concept

No public PoC currently indexed for CVE-2026-35540.

CWE Category CWE-669
Published Date Apr 03, 2026
Modified Date Jul 24, 2026
Exploit Status Not Found
Score 5.4 CVSS v3.1
Exploit Probability (EPSS)
0.31%

Vulnerability Summary

CVE-2026-35540: An issue was discovered in Roundcube Webmail 1.6.0 before 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts.

Impacted Vendors

C
cobalt 1
R
roundcube 1
V
vdesk 1

Reference Links

https://github.com/roundcube/roundcubemail/commit/27ec6cc9cb25e1ef8b4d4ef39ce76d619caa6870 https://github.com/roundcube/roundcubemail/commit/579b68eff90650a5c782e153debd66c765648942 https://github.com/roundcube/roundcubemail/releases/tag/1.6.14 https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5 https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
5.4
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-35540 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected Stack

No specific products linked.