CVE-1999-0399
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 · uneditedThe DCC server command in the Mirc 5.5 client doesn't filter characters from file names properly, allowing remote attackers to place a malicious file in a different location, possibly allowing the attacker to execute commands.
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 confidenceThe DCC (Direct Client-to-Client) server command in mIRC 5.5 does not properly sanitize file names, allowing path traversal characters to be injected. This enables remote attackers to specify arbitrary file paths on the victim's system when receiving files via DCC, potentially overwriting system files or placing executable files in startup locations for subsequent command execution.
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= 5.5CVSS 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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/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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Identify installed mIRC versionCheck the mIRC executable version by right-clicking mirc.exe, selecting Properties, and viewing the Version tab, or use a command-line tool like 'ver' on the mirc.exe pathAffected if The version listed is 5.5 exactly
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Confirm DCC receive is enabledOpen mIRC, go to Tools > Options > DCC > Folders, or check if the DCC Folders section in mIRC options shows any receive folder configuredAffected if A DCC receive folder is set or DCC file receiving is enabled in the client settings
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Check for recent DCC file receive activityReview the DCC receive folder (typically the default 'Received Files' or user-configured path) for any files received via DCC, and check mIRC's message log for DCC GET entriesAffected if There are any files in the receive folder, particularly files with unusual names or from untrusted senders
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Verify DCC server option is activeIn mIRC, check Tools > Options > DCC > Server and confirm if the DCC server option is enabled, which handles incoming DCC connectionsAffected if The DCC server is enabled and accepting incoming connections
A user is affected if they have mIRC version 5.5 installed with DCC file receiving enabled and have used DCC to receive files from other IRC users.
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 to a current version of mIRC or migrate to a modern IRC client, as mIRC 5.5 is end-of-life software with no vendor patches available.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-1999-0399 — 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-1999-0399 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