CVE-1999-1262
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 · uneditedJava in Netscape 4.5 does not properly restrict applets from connecting to other hosts besides the one from which the applet was loaded, which violates the Java security model and could allow remote attackers to conduct unauthorized activities.
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 confidenceNetscape 4.5's Java implementation fails to enforce the same-origin restriction in its security sandbox, allowing loaded applets to open network connections to arbitrary hosts beyond the origin server. This violates the Java security model and enables remote attackers to use applets as unauthorized proxies or for data exfiltration.
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= 4.01= 4.5= 4.06= 4.07= 4.08CVSS 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
- High
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:H/Au:N/C:P/I:P/A:P
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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Verify Netscape Communicator installationSearch for Netscape Communicator executable or installation directory on the system (commonly in Program Files or legacy application folders)Affected if Netscape Communicator is found installed on the system
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Identify installed Netscape versionLaunch Netscape Communicator and check Help > About or examine the executable properties to determine the exact version numberAffected if The version is 4.01, 4.5, 4.06, 4.07, or 4.08
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Confirm Java plugin is enabledIn Netscape Communicator, go to Edit > Preferences > Advanced and verify if Java plugin support is checked or enabledAffected if Java plugin support is enabled in the browser settings
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Test same-origin bypass (if Java console accessible)Load a Java applet from a web server and observe if the applet can make network connections to hosts other than its origin serverAffected if Applet successfully establishes connections to arbitrary hosts violating same-origin policy
User is affected if Netscape Communicator versions 4.01, 4.5, 4.06, 4.07, or 4.08 is installed with Java plugin support enabled, allowing applets to bypass same-origin restrictions.
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 dataDisable Java plugin support in Netscape 4.5, or migrate to a modern browser that receives security updates. There is no vendor patch available for this vintage (1998-1999) software.
- Consultation1.0 h
- Implementation1.0 h
- Testing0.5 h
- Review / QA0.5 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-1999-1262 — 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-1999-1262 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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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.
- 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
- No spam, self-promotion, credentials, or personal data