Is CVE-2021-23253 actively exploited?

No active exploitation of CVE-2021-23253 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-23253 be exploited remotely?

Yes. CVE-2021-23253 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-23253?

CVE-2021-23253 has a CVSS score of 5.3 (MEDIUM).

HOME VULNERABILITIESCVE-2021-23253

MEDIUM

CVE-2021-23253

NVD-CWE-OtherPublished: January 11, 2021· Updated: Jun 17, 2026

5.3

CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2021-23253 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.