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.
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Affected Vendors & Products
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Fixes
Solution
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Workaround
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References
History
Fri, 02 Oct 2026 11:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | Zebra before 6.3.0 Block Sync Denial of Service via Coinbase scriptSig Rewrite | |
| First Time appeared |
Zfnd
Zfnd zebra |
|
| Weaknesses | CWE-345 | |
| CPEs | cpe:2.3:a:zfnd:zebra:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Zfnd
Zfnd zebra |
|
| References |
| |
| Metrics |
cvssV3_1
|
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MITRE
Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-10-02T11:38:03.646Z
Reserved: 2026-10-02T00:46:23.830Z
Link: CVE-2026-104422
Vulnrichment
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NVD
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Redhat
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Weaknesses