8.7
HIGH CVSS 4.0
CVE-2026-123554
Zebra zebrad 6.4.0 before 7.0.0 Denial of Service via Mempool Coinbase-Maturity Check
Description

Zebra zebrad 6.4.0 before 7.0.0 performs quadratic work in the mempool coinbase-maturity check because Transaction::coinbase_spend_restriction() rebuilds the transaction's output list once per spent outpoint. Any connected peer can repeatedly send unsigned transactions with many transparent inputs and outputs, which are rejected without a misbehavior score, to pin verification threads.

INFO

Published Date :

Nov. 8, 2026, 2:16 a.m.

Last Modified :

Nov. 8, 2026, 2:16 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-123554 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Zfnd zebra
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 HIGH MITRE-CVE
CVSS 3.1 HIGH [email protected]
CVSS 4.0 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 HIGH [email protected]
Solution
Update Zebra to version 7.0.0 or later to address performance issues in transaction verification.
  • Update Zebra to version 7.0.0 or later.
  • Apply transaction verification performance improvements.
  • Review and enforce misbehavior scoring for peers.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-123554 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-123554 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-123554 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-123554 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Nov. 08, 2026

    Action Type Old Value New Value
    Added Description Zebra zebrad 6.4.0 before 7.0.0 performs quadratic work in the mempool coinbase-maturity check because Transaction::coinbase_spend_restriction() rebuilds the transaction's output list once per spent outpoint. Any connected peer can repeatedly send unsigned transactions with many transparent inputs and outputs, which are rejected without a misbehavior score, to pin verification threads.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Added CWE CWE-407
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/123xxx/CVE-2026-123554.json">CVE-2026-123554</a>
    Added Reference https://github.com/ZcashFoundation/zebra/commit/08743d669b33a19bce2a5d54001bd468c03a196e
    Added Reference https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-7jp4-mq53-4cvq
    Added Reference https://www.vulncheck.com/advisories/zebra-zebrad-6.4.0-before-7.0.0-denial-of-service-via-mempool-coinbase-maturity-check
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.