BIP375: validate PSBT_OUT_SP_V0_LABEL length #2286

1. 
   wangjingshuiku commented at 9:01 AM on September 12, 2026: contributor

   This PR updates the BIP-375 reference validator to enforce the serialized length of PSBT_OUT_SP_V0_LABEL.

   BIP-375 defines the field value as a 32-bit little-endian unsigned integer, so PSBT_OUT_SP_V0_LABEL must contain exactly 4 bytes. Previously, the validator only checked that PSBT_OUT_SP_V0_LABEL requires PSBT_OUT_SP_V0_INFO, allowing malformed values such as a one-byte label when valid SP_V0_INFO was present.

2. BIP375: validate PSBT_OUT_SP_V0_LABEL length 7ccde10a3c
3. murchandamus requested review from achow101 on Sep 23, 2026
4. 
   murchandamus commented at 10:46 PM on September 23, 2026: member

   cc: @andrewtoth, @josibake, @achow101

5. murchandamus added the label Pending acceptance on Sep 23, 2026
6. murchandamus added the label Bug fix on Sep 23, 2026
7. 
   achow101 commented at 11:38 PM on September 23, 2026: member

   ACK 7ccde10a3c572b75d8fa5a584bf25463156cdcb3

8. jonatack removed the label Pending acceptance on Sep 23, 2026
9. BIP375: add 0.1.2 changelog for LABEL length validation 124324eef1
10. 
    jonatack commented at 5:53 PM on September 27, 2026: member

    ACK 7ccde10a3c572b75d8fa5a584bf25463156cdcb3. Added a changelog entry.

11. jonatack merged this on Sep 27, 2026
12. jonatack closed this on Sep 27, 2026

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Review Requested
achow101