CVE-2026-104431: Asymmetric Resource Consumption (Amplification) in ZcashFoundation zebra
Zebra before 6.0.0 contains a denial of service vulnerability that allows unauthenticated peers to stall Tokio workers by submitting mempool transactions requiring expensive synchronous script verification. Attackers can send non-standard high-sigop P2SH transactions that reach CachedFfiTransaction::is_valid() before standardness checks, saturating the verifier buffer and rendering the node unresponsive.
AI Analysis
Technical Summary
CVE-2026-104431 describes an asymmetric resource consumption vulnerability in ZcashFoundation's Zebra software prior to version 6.0.0. Attackers can exploit this by sending non-standard high-sigop P2SH transactions that bypass standardness checks and reach CachedFfiTransaction::is_valid(), causing expensive synchronous script verification. This saturates the verifier buffer and stalls Tokio workers, resulting in a denial of service condition.
Potential Impact
An unauthenticated attacker can cause a denial of service by making the node unresponsive through resource exhaustion of verification workers. This impacts node availability but does not require authentication or user interaction.
Mitigation Recommendations
A fix is available in Zebra version 6.0.0. Users should upgrade to version 6.0.0 or later to remediate this vulnerability.
CVE-2026-104431: Asymmetric Resource Consumption (Amplification) in ZcashFoundation zebra
Description
Zebra before 6.0.0 contains a denial of service vulnerability that allows unauthenticated peers to stall Tokio workers by submitting mempool transactions requiring expensive synchronous script verification. Attackers can send non-standard high-sigop P2SH transactions that reach CachedFfiTransaction::is_valid() before standardness checks, saturating the verifier buffer and rendering the node unresponsive.
CVSS v4.0
Score 8.7high
Affected software
ZcashFoundation
zebra
pkg:cargo/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-2026-104431 describes an asymmetric resource consumption vulnerability in ZcashFoundation's Zebra software prior to version 6.0.0. Attackers can exploit this by sending non-standard high-sigop P2SH transactions that bypass standardness checks and reach CachedFfiTransaction::is_valid(), causing expensive synchronous script verification. This saturates the verifier buffer and stalls Tokio workers, resulting in a denial of service condition.
Potential Impact
An unauthenticated attacker can cause a denial of service by making the node unresponsive through resource exhaustion of verification workers. This impacts node availability but does not require authentication or user interaction.
Mitigation Recommendations
A fix is available in Zebra version 6.0.0. Users should upgrade to version 6.0.0 or later to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-10-02T00:50:26.603Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6abf99b0a43b0b3b89b26945
Added to database: 10/02/2026, 11:46:56 UTC
Last enriched: 10/02/2026, 12:02:15 UTC
Last updated: 10/03/2026, 03:09:21 UTC
Views: 11
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