/ 
Punk-OAuth2-0.03
/ Punk::OAuth2::JWKS
Security Advisories (1)
CVE-2026-75866 (2026-08-22)

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. 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.

NAME

Punk::OAuth2::JWKS - a cached JWKS key set

SYNOPSIS

my $jwks = Punk::OAuth2::JWKS->new(
	url => 'https://idp.example.com/oauth/jwks.json');

my $key = $jwks->key_for($c, $kid);   # Crypt::JWS::Key or undef

DESCRIPTION

Fetches a JWKS document, imports each entry through "from_jwk" in Crypt::JWS::Key, and caches kid to key per worker, implemented in XS. An unknown kid triggers exactly one (rate-limited) refetch to cover key rotation; a kid still unknown afterwards is negative-cached so attacker-chosen kids cannot become a fetch stream. The URL passes the SSRF guard at construction.

You rarely use this directly - "jwt" in Punk::OAuth2::Checker and the client's OIDC verification build and drive it for you.

METHODS

new

my $jwks = Punk::OAuth2::JWKS->new(
	url         => 'https://idp.example.com/oauth/jwks.json',
	ttl         => 6 * 3600,   # cache lifetime (default 6h)
	ua          => $agent,     # a Fetch-like agent, optional
	allow_local => 0,          # relax the SSRF guard for loopback
);

Croaks if the URL fails the SSRF guard (https, resolves to a public address) unless allow_local is set.

key_for

my $key = $jwks->key_for($c, $kid);

Returns the Crypt::JWS::Key for $kid, fetching (via $c->ua or the configured agent) and caching as needed, or undef. $c may be undef when no request context is available.

AUTHOR

LNATION, <email at lnation.org>

LICENSE AND COPYRIGHT

This software is Copyright (c) 2026 by LNATION <email@lnation.org>.

This is free software, licensed under:

The Artistic License 2.0 (GPL Compatible)