CVE-2012-1251
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 before 9.63 does not properly verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.
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 browser versions before 9.63 fail to properly validate X.509 certificates from SSL servers, allowing man-in-the-middle attackers to spoof legitimate servers and intercept sensitive data by presenting crafted fraudulent certificates.
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<= 9.62= 1.00= 2.00= 2.10= 2.12= 3.00= 3.10= 3.21= 3.50= 3.51= 3.60= 3.61CVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- None
AV:N/AC:M/Au:N/C:P/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 checksWork through these to decide whether this CVE applies to you.
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Check if Opera is installedLook for Opera browser executables or installation directories on the system. Common locations: C:\Program Files\Opera on Windows, /Applications/Opera on macOS, or check the system application list.Affected if Opera Browser is found on the system
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Determine the installed Opera versionOpen Opera, click Help > About Opera, or right-click the Opera executable and select Properties > Details to view the version number.Affected if The version number displayed is 9.62 or lower, or matches one of these: 1.00, 2.00, 2.10, 2.12, 3.00, 3.10, 3.21, 3.50, 3.51, 3.60, 3.61
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Confirm the vulnerability can be triggeredThe vulnerability exists in the SSL/TLS certificate validation code. Any use of Opera to connect to HTTPS websites will rely on the flawed X.509 certificate verification.Affected if The affected version of Opera is used to browse any SSL/TLS-enabled website
If Opera Browser version 9.62 or lower (or versions 1.00 through 3.61 as listed) is installed and used for HTTPS connections, the system is vulnerable to MITM attacks via improperly validated certificates.
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 dataUpgrade Opera to version 9.63 or later, which contains proper X.509 certificate verification logic. For legacy systems still running affected versions, migrate to a modern browser version.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-1251 — 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-2012-1251 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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