Deserialization of Untrusted Data in Roundcube Webmail - #VU156146
Published: October 19, 2026
Vulnerability identifier: #VU156146
CSH Severity: Low
CVSS v4: 2.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-502
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to inject objects during session deserialization, potentially altering application behavior.
The vulnerability exists due to unsafe deserialization in rcube_session::unserialize() when handling session keys prefixed with an exclamation mark. A remote user can supply crafted session data using !-prefixed keys to introduce objects into the deserialization process and potentially affect subsequent application operations.
Affected software
Roundcube Webmail
Remediation
Install security update from vendor's website.
Roundcube Webmail - addressed in versions 1.6.20, 1.7.5