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PatchSiren cyber security CVE debrief

CVE-2026-35679 Zcash CVE debrief

A vulnerability in Zcash zcashd versions prior to 6.12.0 allowed invalid transactions to be accepted under certain conditions, potentially enabling the draining of user funds from the Sprout pool. The root cause was incomplete verification of Sprout proofs in specific scenarios. The issue was resolved in version 6.12.0. The CVSS 3.1 score of 3.5 (Low severity) reflects the attack complexity requirements and limited impact scope. The vulnerability was published on April 5, 2026, with the record last modified on May 19, 2026.

Vendor
Zcash
Product
zcashd
CVSS
LOW 3.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-05
Original CVE updated
2026-07-24
Advisory published
2026-04-05
Advisory updated
2026-07-24

Who should care

Zcash node operators, cryptocurrency exchanges supporting ZEC, wallet providers integrating zcashd, and users with funds in the Sprout shielded pool should prioritize this update.

Technical summary

The vulnerability exists in the Sprout shielded pool implementation of zcashd, where proof verification was not consistently enforced. This cryptographic weakness (CWE-358: Improperly Implemented Security Check for Standard) could allow crafted invalid transactions to bypass validation. The attack requires network access and low privileges, with high attack complexity. The fix in version 6.12.0 ensures proper Sprout proof verification under all conditions.

Defensive priority

medium

Recommended defensive actions

  • Upgrade zcashd to version 6.12.0 or later to ensure proper verification of Sprout proofs.
  • Review transaction logs for the Sprout pool for any anomalous activity during the exposure window if running affected versions.
  • Monitor Zcash security advisories for any additional guidance on this vulnerability.

Evidence notes

The CVE description and NVD record confirm the affected versions and fix version. The GitHub commit and release tag provide technical confirmation of the remediation.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-35679 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-35679

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-35679 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-35679

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.