CVE-2026-104420: Incorrect Type Conversion or Cast in ZcashFoundation zebra
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.
AI Analysis
Technical Summary
CVE-2026-104420 describes a protection mechanism failure in ZcashFoundation's Zebra software prior to version 6.3.0. The vulnerability arises because the inbound cleanup step incorrectly downcasts RouterError to VerifyBlockError, causing the misbehavior score to be discarded. This flaw allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks, enabling attackers to repeatedly force block download and Equihash verification without being banned.
Potential Impact
Attackers can evade the misbehavior scoring system by exploiting the incorrect type conversion, allowing them to repeatedly cause resource-intensive operations such as block download and Equihash verification. This could lead to resource exhaustion or denial of service conditions on affected Zebra nodes. There is no indication of remote code execution or data compromise from the provided data.
Mitigation Recommendations
A fix is available in Zebra version 6.3.0. Users should upgrade to version 6.3.0 or later to remediate this vulnerability. No additional mitigation steps are indicated in the vendor advisory.
CVE-2026-104420: Incorrect Type Conversion or Cast in ZcashFoundation zebra
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.
CVSS v4.0
Score 6.9medium
Affected software
ZcashFoundation
zebra
pkg:github/zcashfoundation/zebraRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-104420 describes a protection mechanism failure in ZcashFoundation's Zebra software prior to version 6.3.0. The vulnerability arises because the inbound cleanup step incorrectly downcasts RouterError to VerifyBlockError, causing the misbehavior score to be discarded. This flaw allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks, enabling attackers to repeatedly force block download and Equihash verification without being banned.
Potential Impact
Attackers can evade the misbehavior scoring system by exploiting the incorrect type conversion, allowing them to repeatedly cause resource-intensive operations such as block download and Equihash verification. This could lead to resource exhaustion or denial of service conditions on affected Zebra nodes. There is no indication of remote code execution or data compromise from the provided data.
Mitigation Recommendations
A fix is available in Zebra version 6.3.0. Users should upgrade to version 6.3.0 or later to remediate this vulnerability. No additional mitigation steps are indicated in the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-10-02T00:46:23.830Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6abf99afa43b0b3b89b268ff
Added to database: 10/02/2026, 11:46:55 UTC
Last enriched: 10/02/2026, 12:16:56 UTC
Last updated: 10/02/2026, 17:49:09 UTC
Views: 4
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