Denial of Service Vulnerability in Zebra by Zcash Foundation
CVE-2026-104431

8.7HIGH

Key Information:

Vendor

Zcashfoundation

Status
Zebra
Vendor
CVE Published:
2 October 2026

What is CVE-2026-104431?

A vulnerability in Zebra prior to version 6.0.0 allows unauthenticated users to cause a denial of service by submitting high-sigop P2SH transactions. This results in the disruption of Tokio workers as it bypasses standard checks, leading to saturation of the verifier buffer. Consequently, nodes may become unresponsive due to the expensive synchronous script verification required for processing these non-standard transactions.

Affected Version(s)

zebra 0 < 6.0.0

zebra 6.0.0

References

https://github.com/ZcashFoundation/zebra/security/advisor...
vendor-advisory
https://www.vulncheck.com/advisories/zebra-before-6.0.0-d...
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

ouicate
conradoplg
.