---
id: "CVE-2026-123558"
page: "https://infrastack.ai/live/CVE-2026-123558"
kind: "vulnerability"
aliases: ["CVE-2026-123558"]
title: "Zebra zebrad: malicious peer can stall checkpoint sync until restart"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["package", "self-hosted", "zcash", "zebrad"]
not_affected_if: ["zebrad-7.0.0-or-later"]
published_at: "2026-11-08T02:16:47+00:00"
first_seen_at: "2026-11-08T02:21:11+00:00"
updated_at: "2026-11-08T02:23:07+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123558", "first_seen_at": "2026-11-08T02:21:11+00:00"}]
exploit_sources: []
---

# Zebra zebrad: malicious peer can stall checkpoint sync until restart

Link for people: https://infrastack.ai/live/CVE-2026-123558 (this .md is for agents)

Zebra's zebrad node, before 7.0.0, can be stalled by a malicious peer that serves a forged block with altered authorizing data followed by a restart-triggering block. The verifier then rejects honest blocks until the node restarts, so the node stops syncing and denial of service results.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the zebrad version with `zebrad --version`; versions below `7.0.0` are in the affected range.
- Look for checkpoint sync stalls in node logs after peer connections.

## Fix

- `zebrad` moves to `7.0.0` or later, per the NVD description.

## Timeline

- 2026-11-08T02:21:11+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123558

## Documents

- [advisory] Vendor advisory: github.com https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-2w9f-9wx8-f5c8
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/zebra-before-7.0.0-checkpoint-sync-denial-of-service-via-cancelled-verifier-rewind

## From the sources

Zebra zebrad before 7.0.0 contains a denial of service vulnerability that allows a malicious peer to stall checkpoint sync by cancelling the verifier rewind after a failed commit. Attackers can serve a forged block with altered authorizing data plus a restart-triggering block, leaving the verifier rejecting honest blocks until restart.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_