CVE-2026-109365 ZcashFoundation CVE debrief

Who should care

Defenders responsible for Zebra instances should assess exposure and prioritize patching to version 6.4.0 or later to prevent potential denial of service attacks. This includes operators, security teams, and vulnerability management teams responsible for Zebra instances. They should review official advisories and CVE records to verify exposure and implement necessary mitigations.

Why it matters

Defenders responsible for Zebra instances should assess exposure and prioritize patching to version 6.4.0 or later to prevent potential denial of service attacks.

• Denial of service attacks may stall Zebra instances for 67 seconds
• Unauthenticated peers can cause wasted proof verification
• Zebra instances may require verification to ensure exposure

Technical summary

The vulnerability in Zebra before 6.4.0 allows unauthenticated peers to cause a denial of service by serving forged block bodies with valid header hashes, leading to wasted proof verification and stalled sync for 67 seconds. This issue is caused by the lack of proper validation of block bodies, allowing attackers to exploit this weakness. The vulnerability affects Zebra instances, potentially stalling them for an extended period. Defenders should assess exposure and prioritize patching to version 6.4.0 or later. The vulnerability is described in the CVE Program record and the NVD vulnerability detail page.

Defensive priority

Medium-priority patching and verification recommended for Zebra instances

Recommended defensive actions

• Patch Zebra instances to version 6.4.0 or later
• Verify Zebra instances for exposure
• Monitor Zebra instances for potential denial of service attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is described in the CVE Program record and the NVD vulnerability detail page. The source item provides additional information about the vulnerability. Evidence is limited to publicly available sources, and defenders should verify exposure using official advisories and CVE records. The source item provides additional context about the vulnerability, but details are limited.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.