How severe is CVE-2020-36178?

CVE-2020-36178 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-36178 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-36178?

CVE-2020-36178 affects Tp-link Tl-wr840n Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-36178?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-36178 published?

CVE-2020-36178 was published on 2021-01-06 and last updated on 2026-06-17.

CVE-2020-36178

CVE-2020-36178 is a critical-severity vulnerability in Tp-link Tl-wr840n Firmware with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 10% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Tp-link Tl-wr840n Firmware
Published: 2021-01-06
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2020-36178?: CVE-2020-36178 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-36178 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-36178?: CVE-2020-36178 affects Tp-link Tl-wr840n Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-36178?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-36178 published?: CVE-2020-36178 was published on 2021-01-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:tp-link:tl-wr840n_firmware:6_eu_0.9.1_4.16:*:*:*:*:*:*:*

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