ZEBRA: Permanent Block Discovery Halt via Gossip Queue Saturation and Syncer Poisoning_CVE-2026-44499

{
    "lastseen": "",
    "description": "ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, a composite denial-of-service vulnerability in Zebra's block discovery pipeline allows an unauthenticated remote attacker to permanently halt all new block discovery on a targeted node. The attack exploits three independent weaknesses in the gossip, syncer, and download subsystems \u2014 all exercisable from a single TCP connection \u2014 to create a monotonically growing block deficit that never self-heals. This issue has been patched in version 4.4.0.",
    "published": "2026-05-08T15:11:24.837Z",
    "modified": "2026-05-08T15:11:24.837Z",
    "type": "cve",
    "title": "ZEBRA: Permanent Block Discovery Halt via Gossip Queue Saturation and Syncer Poisoning",
    "source": "GitHub_M",
    "references": "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-h9hm-m2xj-4rq9",
    "id": "CVE-2026-44499",
    "bulletinFamily": "",
    "cwe": [
        "CWE-770"
    ],
    "cvelist": null,
    "sourceData": "ZcashFoundation zebra < 4.4.0",
    "sourceHref": "",
    "cvss": {
        "score": 8.7,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "zebra",
    "version": "< 4.4.0",
    "vendor": "ZcashFoundation",
    "ai_description": "A composite denial-of-service vulnerability in Zebra's block discovery pipeline allows an unauthenticated remote attacker to permanently halt all new block discovery on a targeted node.",
    "ai_severity": "High",
    "ai_vendor": "Zcash Foundation",
    "ai_product": "Zebra",
    "ai_version": "< 4.4.0",
    "ai_score": 8.7
}