NVD / CVE Program· CNA mitre

CVE-2022-29402: TP-Link TL-WR840N EU v6.20 was discovered to contain insecure protections for its UART console.

Noroxi assessment

Priority: Monitor (action score 27/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.42% (FIRST EPSS).
Physical access to the device is required. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

TP-Link TL-WR840N EU v6.20 was discovered to contain insecure protections for its UART console. This vulnerability allows attackers to connect to the UART port via a serial connection and execute commands as the root user without authentication.

MediumCVSS 6.8 · v3.1—No exploit No fix recorded

Auth bypass

BDU:2022-04739

Published: May 25, 2022
Updated: Jun 17, 2026
EPSS: 0.4% · 36th percentile
CWE: CWE-306

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 27 / 40 · 6.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CNA vs NVD score

NVD: 6.8
CNA · mitre: 6.8; agree

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
tp-link	tl-wr840n firmware	cpe:2.3:o:tp-link:tl-wr840n_firmware
tp-link	tl-wr840n	cpe:2.3:h:tp-link:tl-wr840n

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

tp-link tl-wr840n firmwareall versions

Same product

tp-link: all records

Other highest-scoring records for the same primary product.

CVE-2021-41653The PING function on the TP-Link TL-WR840N EU v5 router with firmware through TL-WR840N(EU)_V5_171211 is vulnerable to remote code execution
62This week
CVE-2018-11714An issue was discovered on TP-Link TL-WR840N v5 00000005 0.9.1 3.16 v0001.0 Build 170608 Rel.58696n and TL-WR841N v13 00000013 0.9.1 4.16 v0
59Plan
CVE-2022-25061TP-LINK TL-WR840N(ES)_V6.20_180709 was discovered to contain a command injection vulnerability via the component oal_setIp6DefaultRoute.
57Plan

Published before and after this one in the same product

← EarlierCVE-2022-26641Mar 28, 2022 · TP-LINK TL-WR840N(ES)_V6.20 was discovered to contain a buffer overflow via the httpRemotePort parameter.
28Monitor
← EarlierCVE-2022-26642Mar 28, 2022 · TP-LINK TL-WR840N(ES)_V6.20 was discovered to contain a buffer overflow via the X_TP_ClonedMACAddress parameter.
28Monitor
← EarlierCVE-2021-46122Apr 18, 2022 · Tp-Link TL-WR840N (EU) v6.20 Firmware (0.9.1 4.17 v0001.0 Build 201124 Rel.64328n) is vulnerable to Buffer Overflow via the Password reset f
28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Physical access to the device is required.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Physical
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-306 · Missing Authentication for Critical Function

CVSS vector

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

nvd-primary

Root cause

A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”

The bug in code

The whole CWE-306 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1// Added for the support team
2app.post("/maintenance/reset", resetDevice);

Fixed

1if (config.maintenanceEnabled) {
2  app.post(
3    "/maintenance/reset",
4    requireSession, requireRole("admin"), resetDevice
5  );
6}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

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Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

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