What is CVE-2026-104431?

CVE-2026-104431 is a high-severity vulnerability in Zcashfoundation Zebra, classified under Asymmetric Resource Consumption (Amplification). CVSS score: 7.5/10. Published 2026-10-02.

How severe is CVE-2026-104431?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Zcashfoundation Zebra

CVE-2026-104431

Zebra before 6.0.0 contains a denial of service vulnerability that allows unauthenticated peers to stall Tokio workers by submitting mempool transactions requiring expensive synchronous script verification. Attackers can send non-standard high-sigop P2SH transactions that reach CachedFfiTransaction::is_valid() before standardness checks, saturating the verifier buffer and rendering the node unresponsive.

Published 2026-10-02 · last modified 2026-10-02.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Zcashfoundation Zebra

Weakness classification (CWE)

CWE-405 — Asymmetric Resource Consumption (Amplification)

References

github.com/ZcashFoundation/zebra/security/advisories/GHSA-84j3-rw4c-gqmj (vendor-advisory)
www.vulncheck.com/advisories/zebra-before-6.0.0-denial-of-service-via-synchrono… (third-party-advisory)

Frequently asked questions

What is CVE-2026-104431?: CVE-2026-104431 is a high-severity vulnerability in Zcashfoundation Zebra, classified under Asymmetric Resource Consumption (Amplification). CVSS score: 7.5/10. Published 2026-10-02.
How severe is CVE-2026-104431?: High severity. CVSS v3 base score is 7.5 out of 10.