CVE-2026-104422Zebra before 6.3.0 Block Sync Denial of Service via Coinbase scriptSig Rewrite
Updated under an hour ago ()
Does this affect you?
It affects ZcashFoundation zebra. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.18%, higher than 7% of scored CVEs.
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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
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-345
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.18% (percentile 7)
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Oct 2, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
ZcashFoundation zebra zcashfoundation:zebra (from the name) | before 6.3.0; 6.3.0 not affected | CNA record |
References
- https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-g95h-hw6g-pvgvvendor-advisory
- https://www.vulncheck.com/advisories/zebra-before-6.3.0-block-sync-denial-of-service-via-coinbase-scriptsig-rewritethird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.