How severe is CVE-2021-27209?

CVE-2021-27209 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-27209 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27209?

CVE-2021-27209 affects Tp-link Archer C5v Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27209?

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

When was CVE-2021-27209 published?

CVE-2021-27209 was published on 2021-02-13 and last updated on 2026-06-17.

CVE-2021-27209

CVE-2021-27209 is a high-severity vulnerability in Tp-link Archer C5v Firmware with a CVSS 3.x base score of 7.1. 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-319.

Key facts

Severity: High (CVSS 3.x base score 7.1)
CVSS v2: 3.6
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-319
Affected product: Tp-link Archer C5v Firmware
Published: 2021-02-13
Last modified: 2026-06-17

Description

In the management interface on TP-Link Archer C5v 1.7_181221 devices, credentials are sent in a base64 format over cleartext HTTP.

Frequently asked questions

What is CVE-2021-27209?: In the management interface on TP-Link Archer C5v 1.7_181221 devices, credentials are sent in a base64 format over cleartext HTTP.
How severe is CVE-2021-27209?: CVE-2021-27209 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-27209 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27209?: CVE-2021-27209 affects Tp-link Archer C5v Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27209?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27209 published?: CVE-2021-27209 was published on 2021-02-13 and last updated on 2026-06-17.

References

https://gokay.org/tp-link-archer-c5v-base64-cookie/

Affected products (1)

cpe:2.3:o:tp-link:archer_c5v_firmware:1.7_181221:*:*:*:*:*:*:*

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