CWE-637
Unnecessary Complexity in Protection Mechanism (Not Using 'Economy of Mechanism')
Monthly
Signature verification bypass in Krajowa Izba Rozliczeniowa (KIR) Szafir SDK before version 463 causes the SDK to return a 'Positively verified' success result (Result/@code == 0) even when the signer's certificate trust could not be established (certificateType == 'nondetermined'). Consuming applications that rely on this result for authentication accept forged or untrusted-chain signatures as valid, enabling authentication bypass and user impersonation. There is no public exploit identified at time of analysis and EPSS probability is low (0.04%), but CISA's SSVC framework rates the technical impact as total and the flaw as automatable.
Signature verification bypass in Krajowa Izba Rozliczeniowa (KIR) Szafir SDK before version 463 causes the SDK to return a 'Positively verified' success result (Result/@code == 0) even when the signer's certificate trust could not be established (certificateType == 'nondetermined'). Consuming applications that rely on this result for authentication accept forged or untrusted-chain signatures as valid, enabling authentication bypass and user impersonation. There is no public exploit identified at time of analysis and EPSS probability is low (0.04%), but CISA's SSVC framework rates the technical impact as total and the flaw as automatable.