CVE-2026-123556

Description

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.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: MEDIUM
CVSS score: 6.9 / 10
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Effective score: 6.9 / 10 MEDIUM source: CNA overview
CWE(s): CWE-693
Reserved: 2026-11-06
Published: 2026-11-08 01:37 UTC
Last updated: 2026-11-08 01:37 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/123xxx/CVE-2026-123556.json

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-119441

EUVD enrichment is queued; refresh the page in a few seconds.

Affected products (1)

Vendor	Product	Versions	Platforms
ZcashFoundation	zebra	`4.5.0` (affected), `7.0.0` (unaffected)	—

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

GitHub Security Advisory (GHSA-5h3r-fpmj-483w) vendor-advisory
VulnCheck Advisory: Zebra 4.5.0 before 7.0.0 Honest Peer Ban via Mempool Lock-Time Scoring third-party-advisory

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

Remediations (10)

October 2026 Critical Patch Update Released | security

web:blogs.oracle.com

For more information about the Critical Patch Update program, see the security vulnerability remediation practices page located on the Oracle Trust Center.

2026-11-08 11:25 UTC
CVE Database Search & Remediation Guidance

web:cvedatabase.com

Search and analyze CVE vulnerabilities with instant access to CVSS scores, affected products, and remediation guidance.

2026-11-08 11:25 UTC
CISA Requires Federal Agencies to Patch Critical Vulnerabilities Within ...

web:cybersecuritynews.com

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued Binding Operational Directive (BOD) 26-04, titled "Prioritizing Security Updates Based on Risk," compelling all Federal Civilian Executive Branch (FCEB) agencies to remediate the most dangerous known exploited vulnerabilities within just three calendar days.

2026-11-08 11:25 UTC
CVE Vulnerabilities 2026: Critical Flaws & Fixes Hub

web:cyberupdates365.com

Track critical CVE vulnerabilities 2026 with verified enterprise patch guides. Fix zero-days across VMware, WordPress, Windows, and cloud infrastructure.

2026-11-08 11:25 UTC
NVD - Search

web:nvd.nist.gov

Search Please make use of the interactive search interfaces to find information in the database!

2026-11-08 11:25 UTC
ArcGIS Server Security 2026 Update 2 Patch - Esri Support

web:support.esri.com

This patch deals specifically with the issues listed below under Issues addressed with this patch . As part of the patch installation, the ArcGIS Server service is stopped and restarted. The restart may take several minutes depending on the number of services published on the ArcGIS Server site. This patch can be uninstalled as outlined in the Uninstalling this patch on Windows and Uninstalling ...

2026-11-08 11:25 UTC
SAP Security Patch Day - October 2026

web:support.sap.com

On 13 th of October 2026 , SAP security patch day saw the release of 16 new security notes and 4 GitHub security advisories. There are 2 updates to previously released security notes.

2026-11-08 11:25 UTC
CVE-2026-123556 - Zebra Node Protection Mechanism Failure…

web:vulmon.com

Vulnerability Summary ZcashFoundation Zebra versions 4.5.0 up to, but not including, 7.0.0 have a protection mechanism failure. This flaw allows attackers to ban honest peers for 24 hours or until restart. Attackers can achieve this by broadcasting transactions locked until the current block height immediately after each new block is mined, causing lagging nodes to incorrectly ban legitimate ...

2026-11-08 11:25 UTC
Vulnerability Remediation vs. Mitigation Explained

web:www.armorcode.com

The Strategic Decision Matrix: When to Remediate vs. Mitigate Prioritization paralysis happens when everything looks urgent. Deciding between remediation and mitigation requires looking past the CVSS score and incorporating actual business context. The framework below walks through the same four factors covered in this section: exploitability, patch availability, asset criticality, and ...

2026-11-08 11:25 UTC
CVE: Common Vulnerabilities and Exposures

web:www.cve.org

At cve .org, we provide the authoritative reference method for publicly known information-security vulnerabilities and exposures

2026-11-08 11:25 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-123556.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:cargo/zebrad",
          "product": "zebra",
          "vendor": "ZcashFoundation",
          "versions": [
            {
              "lessThan": "7.0.0",
              "status": "affected",
              "version": "4.5.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:zfnd:zebra:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.0",
                  "versionStartIncluding": "4.5.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "SphereDonout"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "conradoplg"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "mpguerra"
        }
      ],
      "datePublic": "2026-10-22T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-693",
              "description": "Protection Mechanism Failure",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-08T01:37:58.283Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-5h3r-fpmj-483w)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-5h3r-fpmj-483w"
        },
        {
          "name": "VulnCheck Advisory: Zebra 4.5.0 before 7.0.0 Honest Peer Ban via Mempool Lock-Time Scoring",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/zebra-4.5.0-before-7.0.0-honest-peer-ban-via-mempool-lock-time-scoring"
        }
      ],
      "title": "Zebra 4.5.0 before 7.0.0 Honest Peer Ban via Mempool Lock-Time Scoring",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-123556",
    "datePublished": "2026-11-08T01:37:58.283Z",
    "dateReserved": "2026-11-06T00:50:45.483Z",
    "dateUpdated": "2026-11-08T01:37:58.283Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}