CVE-2020-26160: Authorization bypass in github.com/dgrijalva/jwt-go

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-09-30 · updated 2026-06-17
Weakness: CWE-287

Description

jwt-go before 4.0.0-preview1 allows attackers to bypass intended access restrictions in situations with []string{} for m["aud"] (which is allowed by the specification). Because the type assertion fails, "" is the value of aud. This is a security problem if the JWT token is presented to a service that lacks its own audience check.

Affected products

Jwt-Go Project Jwt-Go: through 3.2.0
Go Github.Com/Dgrijalva/Jwt-Go: from 0.0.0-20150717181359-44718f8a89b0
Go Github.Com/Dgrijalva/Jwt-Go/V4: before 4.0.0-preview1 — fixed in 4.0.0-preview1

How to fix

Upgrade to a fixed version: Go Github.Com/Dgrijalva/Jwt-Go/V4 4.0.0-preview1. Check the vendor advisory for mitigations.

References

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