CVE-2021-23253: Opera Mini

Medium severity, CVSS 5.3. EPSS: 0.8% chance of exploitation in the next 30 days.

Opera Mini for Android below 53.1 displays URL left-aligned in the address field. This allows a malicious attacker to craft a URL with a long domain name, e.g. www.safe.opera.com.attacker.com. With the URL being left-aligned, the user will only see the front part (e.g. www.safe.opera.com…) The exact amount depends on the phone screen size but the attacker can craft a number of different domains and target different phones. Starting with version 53.1 Opera Mini displays long URLs with the top-level domain label aligned to the right of the address field which mitigates the issue.

Affected products

• Opera Opera Mini: before 53.1 (fixed in 53.1)

Published 2021-01-11. Last modified 2026-06-17.