Punk::OAuth2::Server versions through 0.03 for Perl issue access tokens outside a client's registered scopes and grant types because no authorization path reads them

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-75866
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-22 14:16:33 UTC
Updated2026-08-22 14:16:33 UTC
DescriptionPunk::OAuth2::Server versions through 0.03 for Perl issue access tokens outside a client's registered scopes and grant types because no authorization path reads them. Punk::OAuth2::Server::Store registers scopes and grant_types per client and documents both as client registration. token dispatches on the grant_type in the request body, so a client registered for authorization_code alone can ask for client_credentials, and that arm passes the requested scope straight to the minter, which signs it into the at+jwt access token. authorize copies the query scope into the authorization code record without comparing it against the registration, leaving the optional consent hook as the only check between an arbitrary scope and the issued code. redirect_uris on the same client row is read and enforced. A registered client can obtain a correctly signed token carrying any scope it names, and a resource server running Punk::OAuth2::Checker accepts that token and honours the scope. A client registered without a secret authenticates on its client_id alone, so anyone who knows that identifier can request one.

Risk And Classification

Problem Types: CWE-862 | CWE-862 CWE-862 Missing Authorization

References

ReferenceSourceLinkTags
metacpan.org/release/LNATION/Punk-OAuth2-0.03/view/lib/Punk/OAuth2/Server/... 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
datatracker.ietf.org/doc/html/rfc6749 9b29abf9-4ab0-4765-b253-1875cd9b441e datatracker.ietf.org
datatracker.ietf.org/doc/html/rfc6749 9b29abf9-4ab0-4765-b253-1875cd9b441e datatracker.ietf.org
metacpan.org/release/LNATION/Punk-OAuth2-0.04/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to Punk-OAuth2 0.04 or later.

Workarounds

CNA: In a proxy ahead of Punk::OAuth2::Server, reject a token or authorization request that asks for a grant type or scope the client is not registered for.

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