What’s Vulnerable › Vulnerabilities

CVE-2026-109365: Zebra before 6.4.0 Denial of Service via Same-Hash Forged Block Bodies

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-12 · updated 2026-10-15
• Weakness: CWE-345

Description

Zebra before 6.4.0 contains an uncontrolled resource consumption vulnerability that allows unauthenticated peers to force full proof verification by serving forged block bodies with valid header hashes. Attackers can flip authorizing-only bytes such as a coinbase scriptSig, wasting Sapling, Orchard, and Ironwood proof verification without penalty and stalling sync for 67 seconds.

Affected products

• ZcashFoundation zebra: before 6.4.0 — fixed in 6.4.0

How to fix

Upgrade to a fixed version: ZcashFoundation zebra 6.4.0. Check the vendor advisory for mitigations.

References

• https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-3c94-hf7p-g5mf
• https://www.vulncheck.com/advisories/zebra-before-6.4.0-denial-of-service-via-same-hash-forged-block-bodies

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