All vulnerabilities
CVE-2026-104420GHSA-8hh2-hrf2-cqf4

Zebra before 6.3.0 Peer Misbehavior Ban Bypass via Gossiped Blocks

ZcashFoundation zebra
Open in ThreatlineRecord JSON
CVSS
6.9Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.30%Chance of exploitation activity in the next 30 days, higher than 22% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in6.3.0Fixed versionCVE List
Published2 Oct 2026Updated 6 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 6.3.0 contains a protection mechanism failure that allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks. The inbound cleanup step wrongly downcasts RouterError to VerifyBlockError and discards the score, so attackers can repeatedly force block download and Equihash verification without being banned.

Text from CVE List

Affected versions 2

  • zebraaffected: all versions before 6.3.0CVE List
  • zebraunaffected: 6.3.0CVE List

References 2