CVE-2026-123556

MEDIUM 5.3

Zebra 4.5.0 before 7.0.0 Honest Peer Ban via Mempool Lock-Time Scoring

CVSS Score

5.3

EPSS Score

0.0%

EPSS Percentile

0th

ZcashFoundation Zebra from 4.5.0 before 7.0.0 contains a protection mechanism failure that bans honest peers by scoring mempool lock-time rejections at the ban threshold. Attackers can broadcast transactions locked until the current height right after each block, causing lagging nodes to ban honest relaying peers for 24 hours or until restart.

CWE	CWE-693
Vendor	zcashfoundation
Product	zebra
Published	Nov 8, 2026

Stay Ahead of the Next One

Get instant alerts for zcashfoundation zebra

Be the first to know when new medium vulnerabilities affecting zcashfoundation zebra are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected Versions

ZcashFoundation / zebra

4.5.0 < 7.0.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-5h3r-fpmj-483w vulncheck.com: https://www.vulncheck.com/advisories/zebra-4.5.0-before-7.0.0-honest-peer-ban-via-mempool-lock-time-scoring

Credits

🔍 SphereDonout conradoplg mpguerra