-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

0xCERT Security Advisory 0xCERT-2026-0205
============================================================

Advisory-ID:  0xCERT-2026-0205
Severity:     Critical
Published:    2026-07-02T19:43:36.000Z
Updated:      2026-10-08T22:47:33.257Z
Chains:       n/a
URL:          https://www.0xcert.com/advisory/0xCERT-2026-0205

Title: zebrad has consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser

Summary
- -------
zebrad has consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser. You are affected if: 1. You run any version of zebrad up to and including v4.4.1. 2. Your node validates blocks on mainnet, testnet, or any network where both Zebra and zcashd nodes participate.

Details
- -------
Summary
You are affected if: 1. You run any version of zebrad up to and including v4.4.1. 2. Your node validates blocks on mainnet, testnet, or any network where both Zebra and zcashd nodes participate.

Affected
- - zebra-script (rust) <= 6.0.1 — fixed in 7.0.0
- - zebrad (rust) <= 4.4.1 — fixed in 4.5.0

Severity
Critical (CVSS 9.3), as rated by the upstream advisory.

Recommended actions
- - Upgrade zebra-script to 7.0.0 or later
- - Upgrade zebrad to 4.5.0 or later

Source & attribution
This 0xCERT advisory summarises GHSA-gf9r-m956-97qx / CVE-2026-52735 from the GitHub Advisory Database, credited upstream to samsulselfut, mpguerra, arya2: https://github.com/advisories/GHSA-gf9r-m956-97qx. Details may change; refer to the original source for the authoritative record.

References
- ----------
- - https://github.com/advisories/GHSA-gf9r-m956-97qx
- - CVE-2026-52735
- - https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-gf9r-m956-97qx
- - https://github.com/AlfredoG87/zcash_script/blob/v0.4.4/src/script/iter.rs#L104-L115
- - https://github.com/ZcashFoundation/zebra/blob/d4cd662c716382f6397d2a730148025a1ca79fec/zebra-consensus/src/block.rs#L140
- - https://github.com/ZcashFoundation/zebra/blob/d4cd662c716382f6397d2a730148025a1ca79fec/zebra-script/src/lib.rs#L383-L400

Verify with the 0xCERT OpenPGP key: https://www.0xcert.com/pgp.asc
Fingerprint: 5F94 3ED1 1E50 CF31 2128  C493 CCC7 D9EC 9415 723D

-----BEGIN PGP SIGNATURE-----

wrsEARYKAG0FgmrIRpYJEDe9Tbcr+ZxrRRQAAAAAABwAIHNhbHRAbm90YXRp
b25zLm9wZW5wZ3Bqcy5vcmexUeNPwA056bw2JUtw6NOisf5THXm5H072sYRs
AY9YVBYhBGCkkFZbJcT5QWu27ze9Tbcr+ZxrAACwzAEAiQvMUni4rsi6/k9o
RnT9bmOrfEe/DfP6yYPvKShjm7UBAJ+C05IdwpnGjRhJ0yNtqnxYNZ4R0Y8c
LsriIYGs0xQK
=Hzmy
-----END PGP SIGNATURE-----