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VxworksOperating system · Windriver

CVE-2021-29998

CRITICAL · 9.8 CVSS v3.1 Published 2021-04-13
Fix available
A fix is available. Upgrade to 6.5 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
An issue was discovered in Wind River VxWorks before 6.5. There is a possible heap overflow in dhcp client.

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 confidence

A heap overflow vulnerability exists in the DHCP client component of Wind River VxWorks versions prior to 6.5, which could allow remote attackers to execute arbitrary code or cause a denial of service due to improper bounds checking when processing DHCP responses.

MitigationUpgrade to VxWorks 6.5 or later to obtain the patched version. If immediate upgrading is not feasible, network segmentation and firewall rules should be implemented to restrict DHCP client exposure to untrusted networks.

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
VxworksOperating system
Affected:< 6.5
Ruggedcom Win Subscriber Station FirmwareOperating system
Affected:all versions
Scalance X200 4 P Irt FirmwareOperating system
Affected:all versions
Scalance X201 3p Irt FirmwareOperating system
Affected:all versions
Scalance X201 3p Irt Pro FirmwareOperating system
Affected:all versions
Scalance X202 2 Irt FirmwareOperating system
Affected:all versions
Scalance X202 2p Irt FirmwareOperating system
Affected:all versions
Scalance X202 2p Irt Pro FirmwareOperating system
Affected:all versions

CVSS 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
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the operating system or device firmware
    Examine the system or device to determine if it runs Wind River VxWorks or is one of the listed Siemens products (Ruggedcom Win Subscriber Station, Scalance X200 4P Irt, Scalance X201 3p Irt, Scalance X201 3p Irt Pro, Scalance X202 2 Irt, Scalance X202 2p Irt, Scalance X202 2p Irt Pro)
    Affected if The system is identified as Wind River VxWorks or any of the listed Siemens products
  2. Check VxWorks version
    Locate the VxWorks version information through system diagnostics, boot logs, or firmware documentation. Compare your installed version against the affected range of versions prior to 6.5
    Affected if The installed VxWorks version is lower than 6.5
  3. Verify Siemens device firmware version
    Access the device management interface or firmware information to determine the installed firmware version
    Affected if The device is any version of the listed Siemens products (all versions are affected)
  4. Confirm DHCP client is in use
    Check if the DHCP client component is enabled or configured on the system. This may involve reviewing network configuration settings, startup scripts, or system documentation
    Affected if DHCP client is actively used or enabled on the system

Your environment is affected if you are running any version of VxWorks prior to 6.5, or any version of the listed Siemens products, and the DHCP client component is enabled and processing network responses.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 6.5 or later
Fixed in 6.5
Interim mitigation

Upgrade to VxWorks 6.5 or later to obtain the patched version. If immediate upgrading is not feasible, network segmentation and firewall rules should be implemented to restrict DHCP client exposure to untrusted networks.

Recommended fix High confidence

VxWorks 6.5 or later (for VxWorks-based devices); contact Siemens for specific firmware versions for Scalance and Ruggedcom devices

  1. 1. Identify the current VxWorks version running on the affected device by checking the system properties or firmware information
  2. 2. For VxWorks-based devices: upgrade to VxWorks version 6.5 or later to resolve the DHCP client heap overflow vulnerability
  3. 3. For Siemens Scalance X200/X201/X202 series devices: contact Siemens for a firmware update that addresses this vulnerability (these are listed as all versions affected)
  4. 4. For Ruggedcom Win Subscriber Station: contact Siemens/Rockwell Automation for a firmware update
  5. 5. After upgrading, verify the new version is running and confirm the vulnerability is resolved
  6. 6. If direct upgrade is not possible, consider network segmentation to isolate affected devices and reduce attack surface
Caveat Upgrading VxWorks may require application compatibility testing; embedded device firmware upgrades may void warranty or require vendor support

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Vxworks Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA6.0 h
42.0 hours of engineering $7,360
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-29998 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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