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Urgent: Security Flaw in Roundcube Webmail Could Let Hackers Access Your Emails

A serious security flaw has been found in certain versions of Roundcube Webmail, a popular email system. This flaw allows attackers to access email data without logging in, putting sensitive information at risk. Small organisations using affected versions should act quickly to protect their email systems.

25 September 2026

Reference: CVE-2026-48842

1. What is being reported?

Researchers have discovered a vulnerability in Roundcube Webmail versions before 1.6.16 and 1.7.1. This flaw involves a weakness in a plugin that could let attackers run harmful commands on the system without needing a password, potentially exposing emails and user data.

2. What this means in plain English

If your organisation uses the affected Roundcube Webmail versions, hackers could exploit this flaw to read or steal emails and sensitive information. This could lead to data breaches, loss of trust, or other security problems.

3. Could this affect a small business?

Small businesses or charities using Roundcube Webmail with the vulnerable plugin versions are at risk. If you do not use Roundcube Webmail or have updated to the latest versions, you are likely not affected.

4. What to do now

  • Check if your email system uses Roundcube Webmail versions before 1.6.16 or 1.7.1.
  • If affected, update Roundcube Webmail to the latest available version immediately.
  • Ask your IT provider to verify that the virtuser_query plugin is secure or disabled if not needed.
  • Monitor your email system for any unusual activity and report concerns promptly.

5. Ask your IT provider

Can you confirm if our Roundcube Webmail system is affected by CVE-2026-48842 and if it has been updated to fix the SQL injection vulnerability?

6. Bottom line

Keep your email software up to date to prevent hackers from exploiting this serious security flaw.

Information based on CISA KEV, NVD, and reputable security news reports.

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