Opera BrowserApplication · Opera

CVE-2007-3819

MEDIUM · 5.0 CVSS v2.0 Published 2007-07-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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 · unedited
Opera 9.21 allows remote attackers to spoof the data: URI scheme in the address bar via a long URI with trailing whitespace, which prevents the beginning of the URI from being displayed.

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 · moderate confidence

In Opera 9.21, a URI spoofing vulnerability exists where a long URI containing trailing whitespace causes the address bar to display only the end of the URI. This prevents users from seeing the beginning of the URL, potentially hiding the 'data:' scheme prefix and allowing attackers to disguise malicious content as legitimate sites.

MitigationUpgrade to a newer version of Opera that properly handles trailing whitespace in URIs and ensures the address bar displays the complete URI or at minimum the scheme identifier. Until then, users should verify URLs through other means and avoid clicking suspicious links.

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
Opera BrowserApplication
Affected:= 9.21

CVSS 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
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None

AV:N/AC:L/Au:N/C:N/I:P/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 checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Opera Browser is installed
    Locate the Opera executable (opera.exe on Windows, Opera on macOS/Linux) in the system or check program files directories
    Affected if Opera Browser exists on the system
  2. Identify installed Opera version
    Open Opera, then access Help > About Opera or type opera:about in the address bar to display the version information
    Affected if The version shown is exactly 9.21
  3. Verify the URI spoofing condition
    Manually construct a long URI with trailing whitespace (for example: a long string followed by spaces, such as a data: URI with excessive trailing whitespace) and observe how it displays in the address bar
    Affected if The address bar shows only the end portion of the URI and hides the beginning (including potentially the scheme)

If Opera Browser version 9.21 is installed and the address bar truncates long URIs with trailing whitespace to hide the beginning/scheme, the environment is affected by this vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to a newer version of Opera that properly handles trailing whitespace in URIs and ensures the address bar displays the complete URI or at minimum the scheme identifier. Until then, users should verify URLs through other means and avoid clicking suspicious links.

Fix this in Opera Browser Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2007-3819 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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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