All vulnerabilities
CVE-2026-109366GHSA-4f6v-mj46-gxg3

Zebra before 6.4.0 Gossiped Block Drop via Forged Coinbase scriptSig Height

ZcashFoundation zebra
Open in ThreatlineRecord JSON
CVSS
6.3Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.16%Chance of exploitation activity in the next 30 days, higher than 4% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in6.4.0Fixed versionCVE List
Published12 Oct 2026Updated 12 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

Zebra before 6.4.0 contains an improper integrity validation vulnerability in the inbound gossip download path that allows unauthenticated peers to force dropping of new blocks without penalty. Attackers can serve a real block with a coinbase scriptSig rewritten to height 1, which keeps the ZIP-244 block hash, triggering a behind-tip drop before consensus validation and delaying tip discovery for mining backends.

Text from CVE List

Affected versions 2

  • zebraaffected: all versions before 6.4.0CVE List
  • zebraunaffected: 6.4.0CVE List

References 2