What is CVE-2026-104426?

CVE-2026-104426 is a medium-severity vulnerability in Zcashfoundation Zebra, classified under Inefficient Algorithmic Complexity. CVSS score: 5.9/10. Published 2026-10-02.

How severe is CVE-2026-104426?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Vulnerability in Zcashfoundation Zebra

CVE-2026-104426

Zebra before 6.1.0 contains an inefficient algorithmic complexity vulnerability in remaining_transaction_value that clones the entire block-level spent-UTXO map per transaction during contextual verification. Attackers can mine or seed the mempool with roughly 26,000 minimal single-input transactions in one block, stalling every validating node for over 52 seconds.

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

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/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-407 — Inefficient Algorithmic Complexity

References

github.com/ZcashFoundation/zebra/security/advisories/GHSA-4g24-549m-hp75 (vendor-advisory)
www.vulncheck.com/advisories/zebra-before-6.1.0-quadratic-complexity-dos-via-bl… (third-party-advisory)

Frequently asked questions

What is CVE-2026-104426?: CVE-2026-104426 is a medium-severity vulnerability in Zcashfoundation Zebra, classified under Inefficient Algorithmic Complexity. CVSS score: 5.9/10. Published 2026-10-02.
How severe is CVE-2026-104426?: Medium severity. CVSS v3 base score is 5.9 out of 10.