Vulnerability Monitor

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CVE-2020-36178

oal_ipt_addBridgeIsolationRules on TP-Link TL-WR840N 6_EU_0.9.1_4.16 devices allows OS command injection because a raw string entered from the web interface (an IP address field) is used directly for a call to the system library function (for iptables). NOTE: oal_ipt_addBridgeIsolationRules is not the only function that calls util_execSystem.

Security Impact Summary

This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.8, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 2 products from tp-link, from tp-link organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-01-06T21:15:14.317

Last Modified

2024-11-21T05:28:54.057

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 9.8 (CRITICAL)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: COMPLETE
Integrity Impact: COMPLETE
Availability Impact: COMPLETE

Exploitability Score

10.0

Impact Score

10.0

Weaknesses

Type: Primary
CWE-78

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Operating System	tp-link	tl-wr840n_firmware	6_eu_0.9.1_4.16	Yes
Hardware	tp-link	tl-wr840n	-	No

References

https://github.com/therealunicornsecurity/therealunicornsecurity.github.io/blob/master/_posts/2020-10-11-TPLink.md Exploit, Third Party Advisory ([email protected])
https://therealunicornsecurity.github.io/TPLink/ Exploit, Third Party Advisory ([email protected])
https://www.tp-link.com/fr/support/download/tl-wr840n/v6/#Firmware Vendor Advisory ([email protected])
https://github.com/therealunicornsecurity/therealunicornsecurity.github.io/blob/master/_posts/2020-10-11-TPLink.md Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://therealunicornsecurity.github.io/TPLink/ Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.tp-link.com/fr/support/download/tl-wr840n/v6/#Firmware Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For tp-link's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.