CVE-2026-44714: bitcoinj has a ScriptExecution P2PKH/P2WPKH Verification Bypass

ScriptExecution.correctlySpends() contains two fast-path verification bugs for standard P2PKH and native P2WPKH spends in core/src/main/java/org/bitcoinj/script/ScriptExecution.java.

In both branches, bitcoinj verifies an attacker-controlled signature/public-key pair but fails to verify that the public key is the one committed to by the output being spent. As a result, any attacker keypair can satisfy bitcoinj’s local verification for arbitrary P2PKH and P2WPKH outputs.

This doesn’t affect the SPV (simple payment verification) trust model, as this model follows PoW and doesn’t verify input signatures at all.