How severe is CVE-2021-27306?

CVE-2021-27306 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-27306 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27306?

CVE-2021-27306 affects Konghq Kong Gateway. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27306?

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-2021-27306 published?

CVE-2021-27306 was published on 2021-03-18 and last updated on 2026-06-17.

CVE-2021-27306

CVE-2021-27306 is a high-severity vulnerability in Konghq Kong Gateway with a CVSS 3.x base score of 7.5. 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-706.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 4.3
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-706
Affected product: Konghq Kong Gateway
Published: 2021-03-18
Last modified: 2026-06-17

Description

An improper access control vulnerability in the JWT plugin in Kong Gateway prior to 2.3.2.0 allows unauthenticated users access to authenticated routes without a valid token JWT.

Frequently asked questions

What is CVE-2021-27306?: An improper access control vulnerability in the JWT plugin in Kong Gateway prior to 2.3.2.0 allows unauthenticated users access to authenticated routes without a valid token JWT.
How severe is CVE-2021-27306?: CVE-2021-27306 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-27306 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27306?: CVE-2021-27306 affects Konghq Kong Gateway. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27306?: 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-2021-27306 published?: CVE-2021-27306 was published on 2021-03-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:konghq:kong_gateway:*:*:*:*:enterprise:*:*:*

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