All vulnerabilities
CVE-2026-104423GHSA-2p4c-3q4q-p463

Zebra before 6.2.1 Denial of Service via Uncapped V6 Shielded Proof Verification

ZcashFoundation zebra
Open in ThreatlineRecord JSON
CVSS
8.7High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.34%Chance of exploitation activity in the next 30 days, higher than 26% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in6.2.1Fixed versionCVE List
Published2 Oct 2026Updated 2 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 (zebrad) before 6.2.1 contains an asymmetric resource consumption vulnerability that allows unauthenticated peers to stall block verification by pushing V6 mempool transactions with invalid Halo2 proofs. Attackers can flood the shared unprioritized Halo2 verification queue with zero-fee transactions carrying zero-filled Orchard and Ironwood proofs, causing nodes to fall behind the chain tip.

Text from CVE List

Affected versions 2

  • zebraaffected: all versions before 6.2.1CVE List
  • zebraunaffected: 6.2.1CVE List

References 2