CVE-2013-4100
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 · uneditedCryptocat before 2.0.22 has Remote Denial of Service via username
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 confidenceThis is a denial of service vulnerability in Cryptocat versions prior to 2.0.22. The vulnerability is triggered by a specially crafted username that causes the application to crash or become unresponsive when processed, likely due to improper input handling or validation of the username field.
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< 2.0.22CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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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Locate Cryptocat installationSearch for Cryptocat application files on the system - common locations include user application directories (e.g., ~/.cryptocat, %APPDATA%/Cryptocat, or /Applications/Cryptocat on macOS)Affected if Cryptocat application files are found on the system
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Identify installed versionCheck the application's version information - typically found in the application metadata, about dialog, or version file within the Cryptocat installation directoryAffected if Unable to determine version or version shows as installed
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Compare version to affected rangeCompare the identified version number against the affected range: versions prior to 2.0.22 (such as 2.0.21, 2.0.20, etc.) are vulnerableAffected if Installed version is less than 2.0.22 (for example, 2.0.21 or earlier)
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Assess exposure to crafted usernamesDetermine if the Cryptocat client connects to chat rooms or processes usernames from other users - the crash occurs when processing specially crafted usernamesAffected if Vulnerable version is in use and the client connects to chat services where arbitrary usernames can be presented
You are affected if Cryptocat version 2.0.22 or later is not installed and the client is used to connect to chat services where unknown usernames are processed.
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 data2.0.22
Update Cryptocat to version 2.0.22 or later to patch the vulnerability. If immediate update is not possible, consider restricting or validating username input at a network level until the update can be applied.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-4100 — 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-2013-4100 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
- No spam, self-promotion, credentials, or personal data