jwt-go allows excessive memory allocation during header parsing
### Summary Function [`parse.ParseUnverified`](https://github.com/golang-jwt/jwt/blob/c035977d9e11c351f4c05dfeae193923cbab49ee/parser.go#L138-L139) currently splits (via a call to [strings.Split](https://pkg.go.dev/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: [CWE-405: Asymmetric Resource Consumption (Amplification)](https://cwe.mitre.org/data/definitions/405.html) ### Details See [`parse.ParseUnverified`](https://github.com/golang-jwt/jwt/blob/c035977d9e11c351f4c05dfeae193923cbab49ee/parser.go#L138-L139) ### Impact Excessive memory allocation
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-30204US | — | — | ||
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 stri… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/golang-jwt/jwtPACKAGE
- https://github.com/golang-jwt/jwt/commit/0951d184286dece21f73c85673fd308786ffe9c3WEB
- https://github.com/golang-jwt/jwt/commit/bf316c48137a1212f8d0af9288cc9ce8e59f1afbWEB
- https://github.com/golang-jwt/jwt/security/advisories/GHSA-mh63-6h87-95cpWEB
- https://nvd.nist.gov/vuln/detail/CVE-2025-30204ADVISORY
- https://security.netapp.com/advisory/ntap-20250404-0002WEB
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