Quick answers
- Is CVE-2026-104435 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-104435 being exploited in the wild.
- How severe is CVE-2026-104435?
- High severity, with a CVSS score of 7.4, published 2 October 2026.
- Which products and versions are affected?
- Zcash Foundation Zebra-Script 6.0.0; Zcash Foundation Zebrad 4.4.0.
- Is there a fix for CVE-2026-104435?
- Yes: fixed in zebrad 4.4.1, zebra-script 6.0.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-104435 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-104435?
- Check whether you run Zcash Foundation Zebra-Script or Zcash Foundation Zebrad at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: zebrad 4.4.1, zebra-script 6.0.1
Technical details
Zebra fails to enforce ZIP-244 consensus rules for V5 transparent transactions: when an input is signed with SIGHASH_SINGLE and no transparent output exists at the same index, validation must fail. Instead, Zebra's sighash callback forwards to librustzcash, which hashes an empty output set rather than rejecting the invalid case. An attacker can create V5 transactions with more inputs than outputs, sign them with a digest Zebra computes, and broadcast them to cause network partition between Zebra and zcashd nodes.
Affected products
- Zcash Foundation zebrad 4.4.0
- Zcash Foundation zebra-script 6.0.0
Timeline
- 2026-05-04: disclosed: GitHub Security Advisory GHSA-pvmv-cwg8-v6c8 published
- 2026-10-02: advisory: CVE-2026-104435 published on NVD