CVE-2026-104422

The block sync download path in Zebra (zebrad) before 6.3.0 reads a block's height from its unvalidated coinbase scriptSig and drops blocks that appear too far behind the tip before consensus validation, without penalizing the supplying peer. Because V5 transaction IDs exclude the scriptSig, a malicious peer can repeatedly serve a canonical block whose coinbase claims height 1 while keeping the requested hash, delaying the node's discovery of the newest block.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-g95h-hw6g-pvgv
https://www.vulncheck.com/advisories/zebra-before-6.3.0-block-sync-denial-of-service-via-coinbase-scriptsig-rewrite

Configurations

No configuration.

History

02 Oct 2026, 12:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-02 12:17

Updated : 2026-10-02 18:17

NVD link : CVE-2026-104422

Mitre link : CVE-2026-104422

CVE.ORG link : CVE-2026-104422

JSON object : View

Products Affected

No product.

CWE

CWE-345

Insufficient Verification of Data Authenticity

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