Vulnerability Report

CVE-2026-35537

RCE

Title: Unsafe deserialization in Roundcube Webmail session handler

RCE

Proof Of Concept

No public PoC currently indexed for CVE-2026-35537.

CWE Category CWE-502

Published Date Apr 03, 2026

Modified Date Jul 24, 2026

Exploit Status Not Found

Score 3.7 CVSS v3.1

Exploit Probability (EPSS)

0.47%

Vulnerability Summary

CVE-2026-35537: An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Unsafe deserialization in the redis/memcache session handler may lead to arbitrary file write operations by unauthenticated attackers via crafted session data.

Impacted Vendors

cobalt 1

roundcube 1

vdesk 1

Reference Links

https://github.com/roundcube/roundcubemail/commit/618c5428edc69fb088e7ac6c89e506dd39df3 https://github.com/roundcube/roundcubemail/commit/6d586cfa4d8a31f7957f7a445aaedd52592a0e74 https://github.com/roundcube/roundcubemail/commit/a4ead994d2f0ea92e4a1603196a197e0d5df1620 https://github.com/roundcube/roundcubemail/releases/tag/1.5.14 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 HIGH

7.5

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:N/I:H/A:N