Advisories for Golang/Github.com/Golang-Jwt/Jwt package

2025

jwt-go allows excessive memory allocation during header parsing

Function parse.ParseUnverified currently splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request whose Authorization header consists of Bearer followed by many period characters, a call to that function incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. Relevant weakness: …

jwt-go allows excessive memory allocation during header parsing

Function parse.ParseUnverified currently splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request whose Authorization header consists of Bearer followed by many period characters, a call to that function incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. Relevant weakness: …

jwt-go allows excessive memory allocation during header parsing

Function parse.ParseUnverified currently splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request whose Authorization header consists of Bearer followed by many period characters, a call to that function incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. Relevant weakness: …

2024

Bad documentation of error handling in ParseWithClaims can lead to potentially dangerous situations

Unclear documentation of the error behavior in ParseWithClaims can lead to situation where users are potentially not checking errors in the way they should be. Especially, if a token is both expired and invalid, the errors returned by ParseWithClaims return both error codes. If users only check for the jwt.ErrTokenExpired using error.Is, they will ignore the embedded jwt.ErrTokenSignatureInvalid and thus potentially accept invalid tokens.