CVE-2021-38425
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 · uneditedeProsima Fast DDS versions prior to 2.4.0 (#2269) are susceptible to exploitation when an attacker sends a specially crafted packet to flood a target device with unwanted traffic, which may result in a denial-of-service condition and information exposure.
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 confidenceeProsima Fast DDS versions before 2.4.0 contain a vulnerability in the RTPS wire protocol implementation where specially crafted packets can be sent to flood a target device, causing denial of service and exposing sensitive information.
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< 2.4.0CVSS 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
- High
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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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Identify installed eProsima Fast DDS versionRun package manager commands or check build artifacts to retrieve the installed Fast DDS version (e.g., dpkg -l, rpm -qa, or inspect library version strings in the installed binaries)Affected if The detected version is below 2.4.0
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Confirm RTPS wire protocol is in useInspect application configuration files or runtime settings to verify that DDS participants are using RTPS for communication (RTPS is the default wire protocol in Fast DDS but verify participant configurations)Affected if RTPS participants are configured and actively communicating on the network
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Check network exposure of RTPS portsAudit firewall rules, networkACLs, or host-based filters to determine if RTPS ports (typically 7400-7404 by default, or custom ports if configured) are accessible from untrusted network segmentsAffected if RTPS ports are open to untrusted or public network interfaces without filtering
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Verify if rate limiting or network segmentation is appliedReview any existing network protection mechanisms such as rate limiting on RTPS ports or network segmentation isolating DDS endpointsAffected if No rate limiting or network segmentation is implemented and the version is vulnerable
Environment is affected if eProsima Fast DDS version is below 2.4.0 and RTPS protocol is enabled with network exposure to untrusted sources.
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.
dbcve · scoped2.4.0
Upgrade eProsima Fast DDS to version 2.4.0 or later to patch the vulnerability. If upgrading is not immediately feasible, restrict network access to DDS endpoints and implement rate limiting on RTPS ports.
Fast DDS 2.4.0 or later
- 1. Identify all systems running Fast DDS instances in your infrastructure
- 2. Check current Fast DDS version on each affected system using package manager or build system (e.g., `dpkg -l | grep fast-dds` or `cmake` configuration)
- 3. Stop any running Fast DDS applications or services before upgrading
- 4. Upgrade Fast DDS to version 2.4.0 or later using your package manager or build from source: obtain Fast DDS 2.4.0+ from GitHub (github.com/eProsima/Fast-DDS)
- 5. Rebuild and redeploy any applications that link against Fast DDS
- 6. Restart Fast DDS services and verify normal operation
- 7. Monitor for any anomalies and validate the patch is applied by checking the new version
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-38425 — 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-2021-38425 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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