Loading vulnerability…
Pre-auth arbitrary file deletion in Roundcube Webmail via redis/memcache session poisoning bypass
CVE-2026-48847 affects Roundcube Webmail 1.6.x before 1.6.16 and 1.7.x before 1.7.1. The vulnerability is described as a pre-authentication arbitrary file deletion issue caused by a session poisoning bypass involving Redis or Memcache-backed session storage. Based on the provided material, an unauthorized attacker can abuse the session poisoning condition before authentication and cause Roundcube to delete attacker-influenced files. The available content does not identify the exact vulnerable function or code path, but it clearly characterizes the flaw as a cache/session handling bypass that results in arbitrary file deletion.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Successful exploitation allows an unauthenticated attacker to trigger deletion of arbitrary files on the target system prior to login. Depending on which files are removed, this can cause application malfunction, denial of service, loss of data, destruction of configuration or state files, and potentially create conditions for further compromise or recovery abuse.
If you can’t patch tonight, do this now.
If immediate patching is not possible, reduce exposure by disabling or avoiding Redis/Memcache-backed session storage where feasible, restricting access to session/cache infrastructure so untrusted parties cannot influence session data, and hardening filesystem permissions to limit the impact of unintended file deletion. No official workaround beyond updating was provided in the supplied advisories.
Patch, then assume compromise.
Upgrade Roundcube Webmail to 1.6.16 or later on the 1.6.x branch, or to 1.7.1 or later on the 1.7.x branch. Where applicable, apply vendor-packaged fixes such as the Debian security updates referenced in the provided content.
No public exploits tracked yet. Mallory keeps watching.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
2 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.