CVE-2021-39306
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 · uneditedA stack buffer overflow was discovered on Realtek RTL8195AM device before 2.0.10, it exists in the client code when an attacker sends a big size Authentication challenge text in WEP security.
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 confidenceA stack buffer overflow vulnerability exists in the client code of Realtek RTL8195AM WiFi devices before firmware version 2.0.10. The overflow occurs when processing an oversized Authentication challenge text in WEP security mode, potentially allowing remote code 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< 2.0.10CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the WiFi chipset or firmware modelCheck the device documentation, web interface, or system logs for 'RTL8195AM' or 'Realtek RTL8195AM' to confirm the hardware model. This may appear in the wireless adapter properties, device manager, or boot logs.Affected if The device is not using Realtek RTL8195AM chipset - if a different chipset is in use, this CVE does not apply.
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Determine the installed firmware versionAccess the device firmware or module information through the web management interface, CLI (at command), or check the firmware file metadata. Look for a version field labeled as firmware version or build number.Affected if The firmware version is less than 2.0.10 (e.g., 2.0.9, 2.0.8, 1.x.x). Versions 2.0.10 and later are not affected.
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Check if WEP security mode is configuredAccess the wireless security settings on the device (via web UI or CLI). Examine the authentication or encryption mode setting. Look for 'WEP' or 'Wired Equivalent Privacy' as the selected security protocol.Affected if WEP security mode is enabled. The vulnerability only triggers when WEP is in use. If WPA, WPA2, WPA3, or open mode is configured, the vulnerable code path is not exercised.
The device is affected if it uses Realtek RTL8195AM firmware below version 2.0.10 AND has WEP security mode enabled, allowing an oversized Authentication challenge to trigger the stack buffer overflow during WEP authentication.
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 · scoped2.0.10
Upgrade Realtek RTL8195AM devices to firmware version 2.0.10 or later to remediate the stack buffer overflow vulnerability.
RTL8195AM Firmware 2.0.10
- Obtain the Realtek RTL8195AM firmware version 2.0.10 or later from the official Realtek or Ameba IoT website
- Access the device's firmware update interface (typically via web-based administration panel, UART, or manufacturer-provided update utility)
- Backup the current device configuration if the update mechanism supports it
- Upload and flash the firmware version 2.0.10 to the RTL8195AM device
- Verify the firmware upgrade was successful by checking the device's firmware version information
- Restart the device to ensure the new firmware is fully operational
- After upgrade, ensure WEP security is disabled and migrate to a more secure Wi-Fi authentication method (WPA2/WPA3) if possible
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-39306 — 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-2021-39306 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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- Version or environment caveats, and links to real fixes
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