vulnerability / NVI-00013192 / Revision 3
zebrad has consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser
GitHub lists this reviewed advisory for zebra-script, zebrad. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
9.3 CRITICAL (4.0)
security-advisories@github.com severity; no combined Null risk score.
0.507%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.43249. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
zebra-script
source listed<= 6.0.1
### Am I affected 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. All default configurations are affected. No feature flags, non-default settings, or special build options are required. ### Summary Zebra's P2SH sigop counter uses a pure-Rust code path that short-circuits on disabled opcodes (such as `OP_CODESEPARATOR`), returning a partial count of zero for any sigops following the disabled opcode. The reference implementation (zcashd) correctly counts through disabled opcodes in its static sigop analysis. This produces a consensus divergence: Zebra accepts blocks that zcashd rejects when the block-wide `MAX_BLOCK_SIGOPS = 20,000` threshold is crossed on one side but not the other. An attacker can exploit this without mining capability. Broadcasting transactions that spend P2SH outputs with malicious redeem scripts is sufficient; any Zebra miner who includes those transactions in a block triggers a chain split between Zebra and zcashd validators. ### Details The P2SH sigop counter at `zebra-script/src/lib.rs:399` calls `scrip
zebrad
source listed<= 4.4.1
### Am I affected 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. All default configurations are affected. No feature flags, non-default settings, or special build options are required. ### Summary Zebra's P2SH sigop counter uses a pure-Rust code path that short-circuits on disabled opcodes (such as `OP_CODESEPARATOR`), returning a partial count of zero for any sigops following the disabled opcode. The reference implementation (zcashd) correctly counts through disabled opcodes in its static sigop analysis. This produces a consensus divergence: Zebra accepts blocks that zcashd rejects when the block-wide `MAX_BLOCK_SIGOPS = 20,000` threshold is crossed on one side but not the other. An attacker can exploit this without mining capability. Broadcasting transactions that spend P2SH outputs with malicious redeem scripts is sufficient; any Zebra miner who includes those transactions in a block triggers a chain split between Zebra and zcashd validators. ### Details The P2SH sigop counter at `zebra-script/src/lib.rs:399` calls `scrip
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-gf9r-m956-97qx ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-52735 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-52735 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.