CVE-2021-23253
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedOpera 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceOpera Mini for Android versions before 53.1 left-aligns URLs in the address bar, allowing attackers to craft long domain names (e.g., www.safe.opera.com.attacker.com) where users only see the legitimate-looking prefix. This is a UI spoofing vulnerability enabling phishing attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 53.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify if Opera Mini for Android is installedCheck device settings under Apps or use ADB command: `adb shell pm list packages | grep opera`Affected if Package name containing 'opera' and 'mini' is found
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Determine installed Opera Mini versionGo to Settings > Apps > Opera Mini > App info, or use ADB: `adb shell dumpsys package com.opera.mini.android | grep versionName`Affected if Version name is present in the output
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Compare version to vulnerability thresholdCompare the installed version number to 53.1 - note that version numbers may display as 53.0.x or similarAffected if Installed version is lower than 53.1 (e.g., 53.0.x, 52.x, 51.x, etc.)
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Observe address bar behavior (optional confirmation)Navigate to a test URL with a long subdomain pattern (e.g., www.example.com.malicious.com) and observe whether the full URL or only the prefix is visible in the address barAffected if URL appears left-aligned and the actual top-level domain is not visible or requires horizontal scrolling
You are affected if Opera Mini for Android is installed with a version number lower than 53.1.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data53.1
Users should upgrade Opera Mini for Android to version 53.1 or later, which right-aligns the top-level domain to reveal the actual URL.
- Consultation1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-23253 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-23253 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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