How severe is CVE-2021-20151?

CVE-2021-20151 has a CVSS 3.x base score of 10.0, 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-2021-20151 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20151?

CVE-2021-20151 affects Trendnet Tew-827dru Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20151?

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-2021-20151 published?

CVE-2021-20151 was published on 2021-12-30 and last updated on 2026-06-17.

CVE-2021-20151

CVE-2021-20151 is a critical-severity vulnerability in Trendnet Tew-827dru Firmware with a CVSS 3.x base score of 10.0. 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-384.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v2: 7.5
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-384
Affected product: Trendnet Tew-827dru Firmware
Published: 2021-12-30
Last modified: 2026-06-17

Description

Trendnet AC2600 TEW-827DRU version 2.08B01 contains a flaw in the session management for the device. The router's management software manages web sessions based on IP address rather than verifying client cookies/session tokens/etc. This allows an attacker (whether from a different computer, different web browser on the same machine, etc.) to take over an existing session. This does require the attacker to be able to spoof or take over original IP address of the original user's session.

Frequently asked questions

What is CVE-2021-20151?: Trendnet AC2600 TEW-827DRU version 2.08B01 contains a flaw in the session management for the device. The router's management software manages web sessions based on IP address rather than verifying client cookies/session tokens/etc. This allows an attacker (whether from a different computer, different web browser on the same machine, etc.) to take over an existing session. This does require the attacker to be able to spoof or take over original IP address of the original user's session.
How severe is CVE-2021-20151?: CVE-2021-20151 has a CVSS 3.x base score of 10.0, 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-2021-20151 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20151?: CVE-2021-20151 affects Trendnet Tew-827dru Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20151?: 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-2021-20151 published?: CVE-2021-20151 was published on 2021-12-30 and last updated on 2026-06-17.

References

https://www.tenable.com/security/research/tra-2021-54

Affected products (1)

cpe:2.3:o:trendnet:tew-827dru_firmware:2.08b01:*:*:*:*:*:*:*

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