How severe is CVE-2021-23253?

CVE-2021-23253 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-23253 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-23253?

CVE-2021-23253 affects Opera Opera Mini. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-23253?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-23253 published?

CVE-2021-23253 was published on 2021-01-11 and last updated on 2026-06-17.

CVE-2021-23253

CVE-2021-23253 is a medium-severity vulnerability in Opera Opera Mini with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Opera Opera Mini
Published: 2021-01-11
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-23253?: 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.
How severe is CVE-2021-23253?: CVE-2021-23253 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-23253 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-23253?: CVE-2021-23253 affects Opera Opera Mini. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-23253?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-23253 published?: CVE-2021-23253 was published on 2021-01-11 and last updated on 2026-06-17.

References

https://security.opera.com/address-bar-spoofing-in-opera-mini-opera-security-advisories/

Affected products (1)

cpe:2.3:a:opera:opera_mini:*:*:*:*:*:android:*:*

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