CVE-2025-30204

jwt-go allows excessive memory allocation during header parsing

Description

golang-jwt is a Go implementation of JSON Web Tokens. Starting in version 3.2.0 and prior to versions 5.2.2 and 4.5.2, the function parse.ParseUnverified 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. This issue is fixed in 5.2.2 and 4.5.2.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
EPSS 0.02%
Affected: golang-jwt jwt
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2025-30204?
CVE-2025-30204 has been scored as a high severity vulnerability.
How to fix CVE-2025-30204?
To fix CVE-2025-30204, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-30204 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-30204 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-30204?
CVE-2025-30204 affects golang-jwt jwt.
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