Description
Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 contains an object injection primitive in rcube_session::unserialize(). A session key prefixed with “!” was treated as having no value, and the reconstructed serialized string was emitted with a key but no corresponding value, desynchronizing the remainder of the input so that following session data was interpreted as a serialized value. This yields a PHP object injection primitive for an attacker able to influence stored session data. Upstream fixed this in the commit “Fix object injection primitive in rcube_session::unserialize() via “!”-prefixed session keys”, which rejects such keys.
Affected products
roundcube: webmail
References6
- github.com/roundcube/roundcubemail/commit/833770d3d3c35cfde74cc… Patch
- github.com/roundcube/roundcubemail/commit/93284f3f0e13f99af37fc… Patch
- bugs.debian.org/1151279 Third Party AdvisoryMailing List
- github.com/roundcube/roundcubemail/releases/tag/1.6.20 Release Notes
- github.com/roundcube/roundcubemail/releases/tag/1.7.5 Release Notes
- roundcube.net/news/2026/10/19/security-updates-1.6.20-and-1.7.5 Issue Tracking
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 35 · as of 8 November 2026
- CWE
- CWE-502
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