CVE-2026-104420— Zebra before 6.3.0 Peer Misbehavior Ban Bypass via Gossiped Blocks
Quick assessment
Affected
ZcashFoundation zebra
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Zebra 6.3.0 之前的版本中存在保护机制失效漏洞，允许未经验证的节点通过提供无效的广播区块来逃避行为评分（misbehavior scoring）。在入站清理（inbound cleanup）步骤中，系统错误地将 强制转换为 ，并丢弃了相应的行为评分记录。因此，攻击者可以反复强制发起区块下载和 Equihash 验证过程，而不会被系统封禁。
Possible ATT&CK Techniques 2 AI
T1059 · Command and Scripting Interpreter T1498 · Network Denial of ServiceAffected Version Matrix 2
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| ZcashFoundation | zebra | < 6.3.0 |
affected |
6.3.0 |
unaffected |
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I. Basic Information for CVE-2026-104420
Vulnerability Information
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Vulnerability Title
Zebra before 6.3.0 Peer Misbehavior Ban Bypass via Gossiped Blocks
Source: CVE Program / CVE List V5
Vulnerability Description
Zebra before 6.3.0 contains a protection mechanism failure that allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks. The inbound cleanup step wrongly downcasts RouterError to VerifyBlockError and discards the score, so attackers can repeatedly force block download and Equihash verification without being banned.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
不正确的类型转换
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| ZcashFoundation | zebra | 0 ~ 6.3.0 | - |
|
II. Public POCs for CVE-2026-104420
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Advisories for CVE-2026-104420 (2)
Same Patch Batch · ZcashFoundation · 2026-10-02 · 18 CVEs total
| CVE-2026-104423 | 7.5 HIGH | Zebra before 6.2.1 Denial of Service via Uncapped V6 Shielded Proof Verification |
| CVE-2026-104430 | 7.5 HIGH | Zebra 4.5.0 Consensus Split via P2SH Sigop Overcount |
| CVE-2026-104431 | 7.5 HIGH | Zebra before 6.0.0 Denial of Service via Synchronous Script FFI Verification |
| CVE-2026-104422 | 7.5 HIGH | Zebra before 6.3.0 Block Sync Denial of Service via Coinbase scriptSig Rewrite |
| CVE-2026-104435 | 7.4 HIGH | Zebra 4.4.0 Consensus Divergence via V5 SIGHASH_SINGLE Without Output |
| CVE-2026-104437 | 7.4 HIGH | Zebra before 4.4.0 Consensus Split via SIGHASH_SINGLE Missing-Output Handling |
| CVE-2026-104434 | 6.5 MEDIUM | Zebra before 8.0.0 Denial of Service via z_listunifiedreceivers RPC |
| CVE-2026-104426 | 5.9 MEDIUM | Zebra before 6.1.0 Quadratic Complexity DoS via Block Transparent Value Check |
| CVE-2026-104427 | 5.9 MEDIUM | Zebra before 6.1.0 Chain Stall via Stale parent_error_map Entry |
| CVE-2026-104428 | 5.3 MEDIUM | Zebra before 11.0.0 Denial of Service via getblock Verbosity 2 |
| CVE-2026-104432 | 5.3 MEDIUM | Zebra before 6.3.0 False Readiness via Discarded One-Hash FindBlocks Response |
| CVE-2026-104425 | 5.3 MEDIUM | Zebra before 6.1.0 Batch-Verification Poisoning DoS via Unattributed Pushed Transactions |
| CVE-2026-104429 | 5.3 MEDIUM | Zebra before 6.0.0-rc.0 Per-Peer Mempool Admission Bypass via P2P tx Messages |
| CVE-2026-104421 | 5.3 MEDIUM | Zebra before 6.2.1 Block Download Denial of Service via KnownBlock SentHashes Lockout |
| CVE-2026-104419 | 4.8 MEDIUM | Zebra before 6.3.0 Honest Peer Banning via Far-Ahead FindBlocks Hashes |
| CVE-2026-104424 | 3.7 LOW | Zebra before 6.1.0 Incorrect Block Size Calculation in getblocktemplate |
| CVE-2026-104436 | 3.7 LOW | Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/getheaders Locator Length |
IV. Related Vulnerabilities
Same product: zebra
-
CVE-2026-104437
Zebra before 4.4.0 Consensus Split via SIGHASH_SINGLE Missin -
CVE-2026-104436
Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/ -
CVE-2026-104434
Zebra before 8.0.0 Denial of Service via z_listunifiedreceiv -
CVE-2026-104435
Zebra 4.4.0 Consensus Divergence via V5 SIGHASH_SINGLE Witho -
CVE-2026-104432
Zebra before 6.3.0 False Readiness via Discarded One-Hash Fi
Same vendor: ZcashFoundation
-
CVE-2026-104437
Zebra before 4.4.0 Consensus Split via SIGHASH_SINGLE Missin -
CVE-2026-104436
Zebra before 4.5.0 CPU Amplification via Uncapped getblocks/ -
CVE-2026-104434
Zebra before 8.0.0 Denial of Service via z_listunifiedreceiv -
CVE-2026-104435
Zebra 4.4.0 Consensus Divergence via V5 SIGHASH_SINGLE Witho -
CVE-2026-104431
Zebra before 6.0.0 Denial of Service via Synchronous Script
Same weakness: CWE-704
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CVE-2026-69585
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V. Comments for CVE-2026-104420
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