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.

CVSS 4.0

8.2CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.3% chance of exploitation in the next 30 days; higher than 23% of CVEs (scores of 2026-10-25)

CWE

CWE-407

Published

2026-10-02

Modified

2026-10-02

Record from

the NVD, synced 2026-10-19

References

• https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4g24-549m-hp75
• https://www.vulncheck.com/advisories/zebra-before-6.1.0-quadratic-complexity-dos-via-block-transparent-value-check

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