CVE-2026-4346
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 vulnerability affecting TL-WR850N v3 allows cleartext storage of administrative and Wi-Fi credentials in a region of the device’s flash memory while the serial interface remains enabled and protected by weak authentication. An attacker with physical access and the ability to connect to the serial port can recover sensitive information, including the router’s management password and wireless network key. Successful exploitation can lead to full administrative control of the device and unauthorized access to the associated wireless network.
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 confidenceThe TP-Link TL-WR850N v3 router stores administrative and Wi-Fi credentials in cleartext within a flash memory region. The serial debug interface, while password-protected, uses weak authentication. An attacker with physical access can connect to the serial port, bypass the weak authentication, and read the unencrypted credentials from flash memory, gaining full administrative access and wireless network credentials.
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< 0.9.1_Build251205CVSS 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
- Physical
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:P/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 device modelCheck the router label or admin interface for exact model number (TL-WR850N v3)Affected if Device is not a TP-Link TL-WR850N v3, then not affected by this specific CVE
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Check firmware versionLog into the router admin interface (usually at 192.168.0.1) and look for firmware version under System > Firmware Upgrade or Status page, or check via command: cat /proc/version if telnet is enabledAffected if Firmware version is less than 0.9.1_Build251205 (e.g., 0.9.1_Build2xxx or earlier)
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Verify serial debug interface accessibilityPhysically inspect the router circuit board for exposed serial header pins (typically 4 pins: VCC, TX, RX, GND) near the edge of the PCB; check if these pins are accessible without disassemblyAffected if Serial debug pins are physically exposed or easily accessible on the board
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Check for weak serial authenticationConnect to serial interface at 115200 baud 8N1, attempt login with common weak credentials (admin:admin, root:root, or blank password)Affected if Serial interface uses weak or default credentials, or accepts trivial bypass
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Inspect flash memory for cleartext credentialsVia serial console, use flash read commands (e.g., cat /dev/mtdblock0 or dd if=/dev/mtd0) to dump flash memory and search for plaintext Wi-Fi SSID/password or admin username/password stringsAffected if Readable plaintext credentials are found in flash memory dump
User is affected if they have a TL-WR850N v3 router with firmware below 0.9.1_Build251205 and the serial debug interface is physically accessible with weak authentication, allowing extraction of cleartext credentials from flash memory.
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 · scoped0.9.1_Build251205
Implement encrypted credential storage using secure key derivation and encryption for flash memory, and strengthen serial interface authentication or disable the debug interface if not required.
0.9.1_Build251205 or later TP-Link firmware for TL-WR850N v3
- 1. Visit the official TP-Link support website (www.tp-link.com) and navigate to the TL-WR850N v3 product page.
- 2. Locate the firmware download section and verify availability of version 0.9.1_Build251205 or a later stable release.
- 3. Download the firmware file from the official TP-Link website only.
- 4. Access the router's web management interface and navigate to the System Tools > Firmware Upgrade section.
- 5. Upload the downloaded firmware file and allow the upgrade process to complete (do not power off the device during upgrade).
- 6. After the router restarts, log in and verify the firmware version has been updated.
- 7. As an additional mitigation, restrict physical access to the device to prevent unauthorized serial port access.
- 8. Consider changing the administrative password and Wi-Fi credentials after the firmware upgrade as a security best practice.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-4346 — 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-2026-4346 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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